# U.K. Heat and Buildings Strategy, £450m available to homeowners



## MrCurry (Oct 19, 2021)

So U.K. govt has unveiled its “Heat and Buildings Strategy“ which allocates £450m of budget to providing homeowners with a £5,000 subsidy when they choose an energy efficient heat pump boiler instead of a gas boiler, in the hope that by 2035 no gas boilers are being installed.

A heat pump uses a compressor to capture heat from the source and deliver it into the house where it can circulate around the existing radiator system.  This is like a fridge using a compressor to take heat from inside the fridge and delivering it outside and it’s way more efficient than if you just used electricity to directly warm up heating water like an immersion heater does.

Will it work?  Is £5k enough and will the heat pump manufacturers just set their prices so they’re exactly £5k higher than a gas boiler when they might otherwise have been more competitive?  Most of all, with electric prices rocketing sky high, will the running costs of an electric heat pump system measure up against traditionally fairly cheap gas?  Yes, gas is also pricey at the moment, but air source heat pumps are only efficient when ambient temps outdoors are 5C+.  Get some minus temps in winter and your electric usage with a new air source heat pump can go thru the roof.

One thing‘s for certain - British Gas will be rebranding themselves sometime soon and moving into the heat pump installing business!


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## souljacker (Oct 19, 2021)

These things cost 15k so 5k discount still leaves it out of reach of normal people. A gas boiler is about 3k iirc which is still a major outlay for the average household. They are also massive and require a hot water cylinder.

Basically, if you are rich and live in a big house, they are great. If you live in a flat on a low salary, they are impractical.


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## MrCurry (Oct 19, 2021)

souljacker said:


> These things cost 15k so 5k discount still leaves it out of reach of normal people. A gas boiler is about 3k iirc which is still a major outlay for the average household. They are also massive and require a hot water cylinder.
> 
> Basically, if you are rich and live in a big house, they are great. If you live in a flat on a low salary, they are impractical.


And yet the govt strategy unveiled yesterday makes it clear they are seen as the way of the future for the U.K.

How sure are you of those numbers? £15k sounds ridiculous for an air source heat pump system for a normal sized house. A ground source heat pump that needs a 160m deep borehole in the garden, maybe. Mind you, it’s only the boiler cost which comes into the comparison, not the whole system installation cost (since a heat pump shouldn’t cost more to install than a gas boiler AFAIK).

Also, this is a strategy to set the direction to get to zero gas boilers by 2035, so how things look right now will change a lot. For sure they will not be only for “rich people in a big house“ for long.


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## WouldBe (Oct 19, 2021)

The house needs to be very well insulated as well so that's extra expense on top. 

On the plus side if you're handy with tools you could install it yourself as it doesn't use gas.


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## MrCurry (Oct 19, 2021)

WouldBe said:


> The house needs to be very well insulated as well so that's extra expense on top.
> 
> On the plus side if you're handy with tools you could install it yourself as it doesn't use gas.


I’m sure house insulation improvements will be a further part of the strategy,  but not sure it’s true to say the house “needs to be very well insulated“ for a heat pump to work.

Heatpump systems will come in various sizes so if the BTU output of the heatpump matches that of the gas boiler which would have been installed then house insulation isn’t relevant. If you are improving insulation at the same time as installing a heat pump then you’d be able to have a lower output boiler I suppose.


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## BristolEcho (Oct 19, 2021)

How does this work with private landlords? All the plans sound potentially good until you realise that it requires landlords who often don't want to to replace relatively cheap things let alone whole boiler systems for more expensive options. I've not seen anything that addressed this when I read it yesterday. Same issues with insulate Britain.


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## souljacker (Oct 19, 2021)

MrCurry said:


> And yet the govt strategy unveiled yesterday makes it clear they are seen as the way of the future for the U.K.
> 
> How sure are you of those numbers? £15k sounds ridiculous for an air source heat pump system for a normal sized house. A ground source heat pump that needs a 160m deep borehole in the garden, maybe. Mind you, it’s only the boiler cost which comes into the comparison, not the whole system installation cost (since a heat pump shouldn’t cost more to install than a gas boiler AFAIK).
> 
> Also, this is a strategy to set the direction to get to zero gas boilers by 2035, so how things look right now will change a lot. For sure they will not be only for “rich people in a big house“ for long.


15k was the price quoted on the segment on PM on Radio 4 last night.


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## MickiQ (Oct 19, 2021)

When we had the extension built we replaced the boiler not least because the wall it was attached to had to be knocked down. The new one was a condensing boiler unlike the one it replaced. We had the house insulated at the same time and despite the fact that the system had to drive four more radiators it used 30% less gas than before. That boiler was itself replaced two years ago and our gas consumption again fell by something like 10-15%. Perhaps a better idea would be to spend this money on replacing older boilers and insulating houses and encourage if not compel the use of heat pumps in new builds (along with mandatory EV chargers).  I understand that modern boilers can handle up to 5% hydrogen in the gas so I would think there needs to be  intiatives to improve that.


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## marty21 (Oct 19, 2021)

We had a new gas boiler installed last winter , cost about £4k all in . I'm not shelling out again for a long time hopefully.


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## Sprocket. (Oct 19, 2021)

No doubt British Gas will be telling all their Homecare customers that parts are no longer available for their current boiler and they may as well upgrade now for a reasonable fee.
Bastards.
I found this out from my local gas installation engineer when replacing my boiler last year. 
He knew that no local engineers would touch my previous boiler as only British Gas were snatching all the customers up who had that model. Apparently when the boiler company upgraded to new models British Gas bought all the spares available in the country and scrapped them.
Bastards.


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## cybershot (Oct 19, 2021)

I'm probably due a new boiler soon, current one is 17 years old!  (moved house, slightly annoying as only forked out for a new one 3 years ago)

Would love to move away from gas but as a single person household even with the discount, I can't afford it. I'm not even sure double+ income houses can unless its also going to drastically reduce your bill, which I guess it won't? (without taking into account current energy price rises)


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## moochedit (Oct 19, 2021)

Isn't it expensive on the leccy bill?


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## moochedit (Oct 19, 2021)

Do they require annual services? Always a pain with my gas boiler as it is behind my washing machine which i have to remove for the gas engineer to get to it.


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## hitmouse (Oct 19, 2021)

I reckon they should ask their mates in the DUP for some tips on how to incentivise people to switch to renewable sources of heating.


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## skyscraper101 (Oct 19, 2021)

Pure speculation but perhaps the strategy behind this is to get wealthier households to jump at the opportunity to get a free £5k to upgrade to a heat pump, which in turn will create the scale required to bring down the cost for lower income households in the long term.


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## what (Oct 19, 2021)

moochedit said:


> Isn't it expensive on the leccy bill?



Likely to cost you 2 to 3 times as much to run as gas.


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## nogojones (Oct 19, 2021)

skyscraper101 said:


> Pure speculation but perhaps the strategy behind this is to get wealthier households to jump at the opportunity to get a free £5k to upgrade to a heat pump, which in turn will create the scale required to bring down the cost for lower income households in the long term.


Remember who's doing this and think, is this a rational concept that will improve peoples lives, or are they just bunging their mates £450 mill?


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## Elpenor (Oct 19, 2021)

souljacker said:


> These things cost 15k so 5k discount still leaves it out of reach of normal people. A gas boiler is about 3k iirc which is still a major outlay for the average household. They are also massive and require a hot water cylinder.
> 
> Basically, if you are rich and live in a big house, they are great. If you live in a flat on a low salary, they are impractical.


See also various tax breaks for electric cars which attract a huge premium compared to ICE cars and don’t really have a second hand market.


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## WouldBe (Oct 19, 2021)

moochedit said:


> Do they require annual services? Always a pain with my gas boiler as it is behind my washing machine which i have to remove for the gas engineer to get to it.


Heat pumps (air source) are mounted outside so easily accessible. The ones I looked at recently also had the control panel attached to the heat pump so if you needed to adjust the temp or heating times you had to go outside to do it.


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## skyscraper101 (Oct 19, 2021)

nogojones said:


> Remember who's doing this and think, is it this rational concept that will improve peoples lives, or are they just bunging their mates £450 mill?



Oh I know, I'm certain there wasn't some altruistic intention on the part of the Johnson government however, I could buy that the only way to achieve the kind of scale necessary to to get people converting en masse would be to kick it off by incentivizing the middle to higher income households first. Market forces an all.


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## moochedit (Oct 19, 2021)

WouldBe said:


> Heat pumps (air source) are mounted outside so easily accessible. The ones I looked at recently also had the control panel attached to the heat pump so if you needed to adjust the temp or heating times you had to go outside to do it.



My current gas boiler has a wireless remote control to set the thermostat temp. I would have thought simalar must exist for the electric ones?


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## Leafster (Oct 19, 2021)

MrCurry said:


> I’m sure house insulation improvements will be a further part of the strategy,  but not sure it’s true to say the house “needs to be very well insulated“ for a heat pump to work.
> 
> Heatpump systems will come in various sizes so if the BTU output of the heatpump matches that of the gas boiler which would have been installed then house insulation isn’t relevant. If you are improving insulation at the same time as installing a heat pump then you’d be able to have a lower output boiler I suppose.


The focus should be on insulating the UK's homes first and then consider incentives to switch to cleaner heating methods after. 

As many as 25 million homes in the UK use gas as their heat source. This £5,000 grant for Heat Pumps will only be available to 90,000 homes in the three year plan. It's a drop in the ocean. Even in these 90,000 homes, insulation should be considered first so there's no need to over-spec the heat pumps required. We need to reduce all energy consumption. Not just switch it from gas to electricity. 

If grants were made for proper insulation first then not only would those who currently have gas heating also benefit but those who do switch to Heat Pumps will be able to get smaller systems. When you also consider the life cycles of heating systems, how many people will actually need to switch in the three year period of the Heat Pump Grant. 

The only problem is that insulation isn't "sexy" so wouldn't grab any headlines.


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## MickiQ (Oct 19, 2021)

skyscraper101 said:


> Oh I know, I'm certain there wasn't some altruistic intention on the part of the Johnson government however, I could buy that the only way to achieve the kind of scale necessary to to get people converting en masse would be to kick it off by incentivizing the middle to higher income households first. Market forces an all.


Not in itself a bad idea but middle to higher income households are more likely to replace boilers more frequently and thus have more recent kit that they're reluctant to replace. My own boiler cost me 3 or 4 grand a couple of years ago, now that we're fast approaching the empty nest phase of our lives I can see Mrs Q and I selling up and moving to a smaller house long before the boiler needs to be replaced again which is the only point at which I might consider this. £5K grant or not, I'm not going to spend £10K of my own money just to reduce my carbon footprint.


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## quimcunx (Oct 19, 2021)

WouldBe said:


> Heat pumps (air source) are mounted outside so easily accessible. The ones I looked at recently also had the control panel attached to the heat pump so if you needed to adjust the temp or heating times you had to go outside to do it.



I could see this being tricky on a 3rd floor flat.


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## JimW (Oct 19, 2021)

One of my old flats in the city was heated by a communal groundsource pump and was dirt cheap (flat fee and my landlord included it in rent) even with the much colder winters. Would be fantastic to see more of that.


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## platinumsage (Oct 19, 2021)

Leafster said:


> As many as 25 million homes in the UK use gas as their heat source. This £5,000 grant for Heat Pumps will only be available to 90,000 homes in the three year plan. It's a drop in the ocean.



I think the idea is that this will help ramp up installation of these things, bringing the price down. Availability of installers is already tight at the moment - if they offered massive subsidies immediately there just wouldn't be the capacity for the vast majority of people to take them up. So I guess if it's done this way the wealthier pay more to be early adopters, helping to train up more installers.


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## WouldBe (Oct 19, 2021)

moochedit said:


> My current gas boiler has a wireless remote control to set the thermostat temp. I would have thought simalar must exist for the electric ones?


Not that I could see.


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## JoeyBoy (Oct 19, 2021)

I live in a block of 8 flats (owned by 3 different landlords) would we have one of those things for the whole block or one each? If it's a communal one who is going to pay for the leccy to run it? Who gets to decide when it gets switched on?
I leave my gas key out as long for possible to save on the standing charge but if one of these things heats the whole block then I can forsee many arguments as to when it gets turned on, who should pay for that, whose freeloading on other tenants leccy bills. Who pays for the thing to be installed anyway. The cheap cunt who owns mine owns four of the others  and you'd expect him to pay five-eights but I know damn well he won't want to pay more than a third even if the council sends someone to break his legs to get him to pay anything.


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## Sprocket. (Oct 19, 2021)

Typical Tories, if they can’t wipe us out with Covid and related illnesses ramped up by effect on NHS, they’ll just freeze us out.


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## Leafster (Oct 19, 2021)

platinumsage said:


> I think the idea is that this will help ramp up installation of these things, bringing the price down. Availability of installers is already tight - if they offered massive subsidies immediately there just wouldn't be the capacity for the vast majority of people to take them up.


Yeah, I get that. But it's only being offered for a three year period. Currently, around 30,000 Heat Pumps are installed annually. I can't see that a grant which is only available for three years and effectively only subsidises the existing level of installations will have any major impact on encouraging a greater uptake. 

The government's own 10 Point Plan (from last November) states "We will aim for 600,000 heat pump installations per year by 2028" so how are they going to meet the shortfall? I accept that a grant might encourage some further uptake above the existing level of installations but is it likely to double it? I can't see that. Even if it did, then we'd see just a tenth of the government's stated aim of 600,000 per year. 

One of the problems the installers of green tech continually face is that successive governments' strategy has always been very short term. They offer grants for a short period and make changes in what is or isn't covered. It doesn't make it easy for installers to plan ahead in terms of hiring and training staff, investing in equipment or developing technology when the market for their products could be drastically reduced at the whim of some policy change.


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## MrCurry (Oct 19, 2021)

souljacker said:


> 15k was the price quoted on the segment on PM on Radio 4 last night.


Fair enough. Just listened to it here (from 36:10).  A couple of things. The posh guy in Putney who paid £15k for his shiny new system was undoubtedly ripped off and suffered for being (a) a posh twat whose supplier saw him coming (b) an early adopter in a market which is lacking competition in this space so far.  He probably got Pimlico plumbers to install it. 

I have some perspective on this because I paid less than £15k to get a ground source heat pump system installed into my house in Sweden four years ago, and that included drilling 180m deep borehole in the back garden. Heat pumps are very widely used over here, both air source and ground source and the latter cost more to install but are more efficient to run because they can pull +8C out the ground while the ambient is -15C in winter.

Since air source installations are much cheaper to install and everything costs less in U.K. than here, plus U.K. houses are smaller, I’d expect once the market gets competitive you’ll get down to £8-10k turnkey prices, less the £5k subsidy that’s making them comparable to gas boilers which is the whole point of the policy they announced yesterday.

The expert who was put on air by R4 to explain heat pumps did a sucky job, talking about refrigerant liquid / gas states instead of simply telling people what a heat pump does. All she needed to say was they use electricity to pump the heat from the air outside, into the house heating and hot water system.


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## MrCurry (Oct 19, 2021)

moochedit said:


> Isn't it expensive on the leccy bill?


My electric bill came down significantly after getting a heat pump system installed, mainly because it produces hot water much more efficiently than the previous electric immersion tank.


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## MrCurry (Oct 19, 2021)

moochedit said:


> Do they require annual services? Always a pain with my gas boiler as it is behind my washing machine which i have to remove for the gas engineer to get to it.


Some filters to be cleaned every two years, which you could easily do yourself if you read the manual. I’m sure that won’t stop the installers selling people expensive service contracts though, they won’t miss that trick.


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## MrCurry (Oct 19, 2021)

skyscraper101 said:


> Pure speculation but perhaps the strategy behind this is to get wealthier households to jump at the opportunity to get a free £5k to upgrade to a heat pump, which in turn will create the scale required to bring down the cost for lower income households in the long term.


Probably yes. If they’re looking to switch the bulk of the U.K. housing stock from one type of heating to another they will need to do it in stages in any case.  As the economics of these systems change over time they‘ll doubtless change the incentives.


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## MrCurry (Oct 19, 2021)

nogojones said:


> Remember who's doing this and think, is it this rational concept that will improve peoples lives, or are they just bunging their mates £450 mill?


fair point! I wonder how many Tories bought shares in heat pump companies while this was all at consultation stage.


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## moochedit (Oct 19, 2021)

MrCurry said:


> My electric bill came down significantly after getting a heat pump system installed, mainly because it produces hot water much more efficiently than the previous electric immersion tank.



I don't have an electric immersion tank just a gas combi boiler so in my case my electric bill would go up although partly offset by having no gas bill (my oven is electric).


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## JimW (Oct 19, 2021)

JoeyBoy said:


> I live in a block of 8 flats (owned by 3 different landlords) would we have one of those things for the whole block or one each? If it's a communal one who is going to pay for the leccy to run it? Who gets to decide when it gets switched on?
> I leave my gas key out as long for possible to save on the standing charge but if one of these things heats the whole block then I can forsee many arguments as to when it gets turned on, who should pay for that, whose freeloading on other tenants leccy bills. Who pays for the thing to be installed anyway. The cheap cunt who owns mine owns four of the others  and you'd expect him to pay five-eights but I know damn well he won't want to pay more than a third even if the council sends someone to break his legs to get him to pay anything.


Heating on day is November 15 still for Beijing and people largely put up with one size fits all (obviously you can use a bar heater before etc if you want/can afford), date does sometimes get brought forward in a cold snap. Obviously legacy of state control affects attitudes.
Out in country now and have electric powered underfloor pipes, theres a subsidised night leccy rate for that that similarly only applies in winter months.


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## MrCurry (Oct 19, 2021)

moochedit said:


> I don't have an electric immersion tank just a gas combi boiler so in my case my electric bill would go up although partly offset by having no gas bill (my oven is electric).


Yes.  I don’t think anyone can say how much it would rise by, but as long as you’re not amongst the earliest of adopters there will be plenty of anecdotal evidence from others as to how their new heat pump electric bill compares to their old electric + gas bills.  Might be more favourable than you think though, since heat pumps are basically very efficient which is why they’re low carbon.


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## what (Oct 19, 2021)

MrCurry said:


> Yes.  I don’t think anyone can say how much it would rise by, but as long as you’re not amongst the earliest of adopters there will be plenty of anecdotal evidence from others as to how their new heat pump electric bill compares to their old electric + gas bills.  Might be more favourable than you think though, since heat pumps are basically very efficient which is why they’re low carbon.


The only large scale field test of heat pumps in the UK showed an average COP of 2, i.e for each unit of electricity you get 2 units of heat. So as elecy is 5 times the cost of gas per KWh the bill should rise by 5/2 or 2.5 times. Thats if you are lucky enough to get a COP of 2.


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## MrCurry (Oct 19, 2021)

what said:


> The only large scale field test of heat pumps in the UK showed an average COP of 2, i.e for each unit of electricity you get 2 units of heat. So as elecy is 5 times the cost of gas per KWh the bill should rise by 5/2 or 2.5 times. Thats if you are lucky enough to get a COP of 2.


Interesting. I’d expect a lot more than 2, as ambient temps in U.K. are rarely below -3C.  What were the conditions of this test and who published it? What kind of air source heat pumps - the specialised ones designed for whole home heating and hot water, or the type that is basically an air conditioner but can be run in reverse to blow warm air indoors for heating?


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## what (Oct 19, 2021)

what said:


> The only large scale field test of heat pumps in the UK showed an average COP of 2, i.e for each unit of electricity you get 2 units of heat. So as elecy is 5 times the cost of gas per KWh the bill should rise by 5/2 or 2.5 times. Thats if you are lucky enough to get a COP of 2.


It was done by the energy saving trust. link here



			https://energysavingtrust.org.uk/sites/default/files/EST_Heat_Pump_Trials%20part%202a.pdf


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## Leafster (Oct 19, 2021)

what said:


> It was done by the energy saving trust. link here
> 
> 
> 
> https://energysavingtrust.org.uk/sites/default/files/EST_Heat_Pump_Trials%20part%202a.pdf


I wonder if there's been any improvement in performance since that EST trail was done in 2010. 

I had been led to believe that you'd expect a COP of between 3 to 4 nowadays. Although I think they're still saying ground source heat pumps will be more efficient than air source ones.


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## what (Oct 19, 2021)

Leafster said:


> I wonder if there's been any improvement in performance since that EST trail was done in 2010.
> 
> I had been led to believe that you'd expect a COP of between 3 to 4 nowadays. Although I think they're still saying ground source heat pumps will be more efficient than air source ones.


The COP of 3 to 4 is manufacturers claims and does not differ much from around 2010 when the trials were done


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## MrCurry (Oct 19, 2021)

what said:


> It was done by the energy saving trust. link here
> 
> 
> 
> https://energysavingtrust.org.uk/sites/default/files/EST_Heat_Pump_Trials%20part%202a.pdf


Interesting info, thanks. It’s better than nothing, but fairly limited anyway, since they only looked at 29 installations with air source heat pumps and 54 with ground source and there must’ve been huge variations in the system types as they covered all of these various situations:

*Heat pumps installed in private and social housing
properties
••Heat pumps installed in new-build and retrofit installations
••Heat pumps providing heating only
••Heat pumps providing heating and hot water
••Heat pumps installed with different heat delivery systems: under-floor heating and/or radiators

It says the ground source systems included both ground loop (ie. just below the surface) and borehole systems, so the varying results from 1.2 COP up to 3.2 is not surprising given the ground loop ones would have very cold heat sources during winter.

I don’t think those results from Nov 2008 would be representative of what well designed and properly installed systems should deliver in 2022 onwards, but as a worst case scenario your COP 2.0 assumption is probably fair.


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## Saul Goodman (Oct 19, 2021)

My mate uses ground source heat pumps to heat his building. He reckons he's getting a COP of ~4. Air source were around 2 at the time he had them installed (around 5 years ago).


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## MrCurry (Oct 19, 2021)

Saul Goodman said:


> My mate uses ground source heat pumps to heat his building. He reckons he's getting a COP of ~4. Air source were around 2 at the time he had them installed (around 5 years ago).


How does he measure the energy input and output from the heatpump to be able to calculate the COP?  Would need some very specialist equipment I would think.


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## Saul Goodman (Oct 19, 2021)

MrCurry said:


> How does he measure the energy input and output from the heatpump to be able to calculate the COP?  Would need some very specialist equipment I would think.


I doubt you'd need any specialist equipment, just the necessary knowledge to perform the calculations, and his area of expertise is radiators and heat exchangers (he designs and builds them), so I guess he knows how to calculate it.


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## MrCurry (Oct 19, 2021)

Saul Goodman said:


> I doubt you'd need any specialist equipment, just the necessary knowledge to perform the calculations, and his area of expertise is radiators and heat exchangers (he designs and builds them), so I guess he knows how to calculate it.


How would you have the numbers to perform the calculations without measuring equipment?


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## weltweit (Oct 19, 2021)

There are an estimated 27.8 million UK households, that £450m makes £16.80 each 

Estimated UK homeowners 14.6 million households which would be £30.82 each

Not going to get much heat source pumps for that.


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## Saul Goodman (Oct 19, 2021)

MrCurry said:


> How would you have the numbers to perform the calculations without measuring equipment?


I'm guessing because heat exchange is a science he's well educated in. Like I said, he builds radiators and heat exchangers, so I'm guessing he knows how heat transfer works, but I can pass on your contact details to him if you'd like to quiz him about it?


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## MrCurry (Oct 19, 2021)

Saul Goodman said:


> I'm guessing because heat exchange is a science he's well educated in. Like I said, he builds radiators and heat exchangers, so I'm guessing he knows how heat transfer works, but I can pass on your contact details to him if you'd like to quiz him about it?


No, that’s ok.  It’s just the COP is the total energy output from the system over a period of time (ideally a year) divided by the energy consumed.  So I’m not sure how you could calculate that without measurements, however much you know about heat exchange science.  But nevermind, I didn’t mean to give you the third degree about it. If he’s getting 4, that’s very good.


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## moochedit (Oct 19, 2021)

How long til the phone scammers get into this?


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## Riklet (Oct 19, 2021)

Fucking glad im moving somewhere with a good modern condenser boiler personally!

Air source heat pumps are an inappropriate solution for the UK's crappy leaky old housing stock. A lot more could be achieved with less. This is, as ever, a shameless attempt to pump a load of money into the private sector (mmm green capitalists), regardless of whether it's really right in the short medium or long term.

IMO the money should be spent on insulating and improving housing generally. In Scandanvia they have triple glazed windows and solidly built housing... that needs to come first. This would help with addressing both emissions and poor living conditions. A load of barely qualified dudes putting in air source pumps isnt going to achieve much.

If the gov were really serious and wanted to spend big money, what about:


Massive investment in district heating
Use the existing natural gas system for hydrogen and encourage hydrogen boilers
Provide air and ground heat pumps for big buildings and blocks first as communal heating
Good old solar panels on roofs and grants for this plus battery storage and water heating. Could even be done for  whole streets.


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## WouldBe (Oct 19, 2021)

Riklet said:


> Fucking glad im moving somewhere with a good modern condenser boiler personally!
> 
> Air source heat pumps are an inappropriate solution for the UK's crappy leaky old housing stock. A lot more could be achieved with less. This is, as ever, a shameless attempt to pump a load of money into the private sector (mmm green capitalists), regardless of whether it's really right in the short medium or long term.
> 
> ...


Spot on. Hydrogen is a far better way to go. If everything goes electric the entire electrical grid will need to be upgraded when loads of energy could be pumped through the gas pipes.


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## StoneRoad (Oct 19, 2021)

Not impressed with the idea of pumping hydrogen about, unless they have a way of making it less likely to catch fire / blow up if any leaks / escapes from custody.

And I would expect that most pipework would need upgrading


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## Artaxerxes (Oct 19, 2021)

MrCurry said:


> No, that’s ok.  It’s just the COP is the total energy output from the system over a period of time (ideally a year) divided by the energy consumed.  So I’m not sure how you could calculate that without measurements, however much you know about heat exchange science.  But nevermind, I didn’t mean to give you the third degree about it. If he’s getting 4, that’s very good.



I assume if he's living in a house and he's gone to the effort of installing this shit he's taken measurements.


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## WouldBe (Oct 19, 2021)

StoneRoad said:


> Not impressed with the idea of pumping hydrogen about, unless they have a way of making it less likely to catch fire / blow up if any leaks / escapes from custody.


Not a lot different then to the current methane we use.


StoneRoad said:


> And I would expect that most pipework would need upgrading


Most of the grid has been upgraded to something I thought was ok with hydrogen. There will be problems in Leeds if they go ahead with the hydrogen trial and the pipes can't cope with it.


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## bluescreen (Oct 19, 2021)

I have a dumb question for people who have heat pumps: are they noisy? Do the neighbours find them noisy?


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## WouldBe (Oct 19, 2021)

bluescreen said:


> I have a dumb question for people who have heat pumps: are they noisy? Do the neighbours find them noisy?


They can be. Advice I saw when looking was to go and have a look at one working before deciding.


----------



## mentalchik (Oct 20, 2021)

quimcunx said:


> I could see this being tricky on a 3rd floor flat.


Yes....i live in a fifth floor flat in a huge block (one half HA and council, other half private).....how would any of this work...literally hundreds of flats


----------



## Sprocket. (Oct 20, 2021)

bluescreen said:


> I have a dumb question for people who have heat pumps: are they noisy? Do the neighbours find them noisy?


My neighbour who has heard one in use told me that particular model was similar to having a large electric air compressor constantly running.
Nice in the middle of the night when surrounded by them I surmise.


----------



## StoneRoad (Oct 20, 2021)

Yeah, I have heard heat pumps - they can be quite noisy, much louder than the refrigerator comparison usually touted, more like a low pressure / high volume compressor.

IF, it runs continuously, it would just add "white noise" to increase the background noise pollution. I would probably be able to tune that out --- but if it stops and starts, nope, that would be very intrusive. [I have a freezer in an outbuilding with a noisy compressor and I can hear that at night if it cuts in, if the door to the outbuilding is open for the visiting cat to explore]

I live in an area that is currently very quiet at night. If the wind is in the right direction I can just hear a railway and major road that are about two / three miles away ...


----------



## MickiQ (Oct 20, 2021)

StoneRoad said:


> Not impressed with the idea of pumping hydrogen about, unless they have a way of making it less likely to catch fire / blow up if any leaks / escapes from custody.
> 
> And I would expect that most pipework would need upgrading


The Hindenburg going boom is one of those things that has fixed itself firmly in the public pysche but hydrogen is actually less explosive than natural gas (mostly methane) it only has about a fifth the energy density which means more has to be burnt to get the same amount of heat but it's clean only producing water vapour rather than water vapour and carbon dioxide like methane. The big problems with hydrogen are that the molecule is tiny compared to methane making it much more work to seal pipes and the fact it doesn't exist freely in nature for long, it has to be cracked out of something first (ideally water) which requires energy. 
Hydrogen would be the perfect fuel in a post-fusion industrial world, using cheap energy from the reactor it could be cracked out of seawater to burn in internal combustion engines, gas boilers and turbines, power fuel cells and of course fuel the fusion reactors themselves. The massive flaw in that plan is of course we are still some years from a practical working fusion reactor but it could be cracked with renewable energy in the meantime.


----------



## Elpenor (Oct 20, 2021)

My former employer used heat pumps at their office, they’re in a joint venture with another company for producing them in this country I think.

Recall they made a humming sound as you walked past.


----------



## bluescreen (Oct 20, 2021)

StoneRoad said:


> Yeah, I have heard heat pumps - they can be quite noisy, much louder than the refrigerator comparison usually touted, more like a low pressure / high volume compressor.
> 
> IF, it runs continuously, it would just add "white noise" to increase the background noise pollution. I would probably be able to tune that out --- but if it stops and starts, nope, that would be very intrusive. [I have a freezer in an outbuilding with a noisy compressor and I can hear that at night if it cuts in, if the door to the outbuilding is open for the visiting cat to explore]
> 
> I live in an area that is currently very quiet at night. If the wind is in the right direction I can just hear a railway and major road that are about two / three miles away ...


That sounds like where I live. But the care home over the road installed something a while back that has a noisy compressor running all the time, which is quite intrusive at night. Can't imagine what it would be like if all the neighbours were doing it. I'm quite keen to get one but the noise is a problem for me as I have mild misophonia anyway.


----------



## equationgirl (Oct 20, 2021)

I don't know how these are going to work for properties that can't be easily insulated and/or blocks of flats.


----------



## teuchter (Oct 20, 2021)

Has anyone actually read the strategy document? It is here



			https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1026507/heat-buildings-strategy.pdf
		


It's not proposing heat pumps as a solution for everyone. It's proposing funding to encourage a relatively small number of early adopters to start using them and establish them as a more mainstream option.

The strategy also has stuff about hydrogen.


----------



## trashpony (Oct 20, 2021)

20% of U.K. housing stock (including my house) was built pre 1920 meaning it most likely has solid rather than cavity walls. Heat pumps are pointless without good insulation. Is the government going to rehouse us all?


----------



## Elpenor (Oct 20, 2021)

trashpony said:


> 20% of U.K. housing stock (including my house) was built pre 1920 meaning it most likely has solid rather than cavity walls. Heat pumps are pointless without good insulation. Is the government going to rehouse us all?


This is the problem. Attack the problem from the bottom up.


----------



## teuchter (Oct 20, 2021)

It's a problem that has to be attacked from multiple angles. It makes sense to promote the use of heat pumps in properties where it's appropriate.


----------



## WouldBe (Oct 20, 2021)

I'm still not convinced they actually work as they appear to be over unity devices. A heat exchanger can't amplify the temperature of something so the extra heat must come from the compressor but again it can't be over unity. The only way I can see it working without breaking the laws of physics is if the heat generated by compressing the gas is more efficient than using a heating element.


----------



## StoneRoad (Oct 20, 2021)

Updating the housing stock would be a massive undertaking - and there is quite a lot of potential for other problems.
I'm thinking specifically of the "embeded" carbon in the old building and ditto for the replacement.









						Don't demolish old buildings, urge architects
					

Knocking down defunct structures sends a wrecking ball through carbon targets, architects say.



					www.bbc.co.uk


----------



## teuchter (Oct 20, 2021)

WouldBe said:


> I'm still not convinced they actually work as they appear to be over unity devices. A heat exchanger can't amplify the temperature of something so the extra heat must come from the compressor but again it can't be over unity. The only way I can see it working without breaking the laws of physics is if the heat generated by compressing the gas is more efficient than using a heating element.


It just moves energy that's outside the house, into the house. The outside air gets slightly colder and the water circulating in the heating inside the house gets warmer.

Although it's true they work by magic, they don't create any free energy.


----------



## WouldBe (Oct 20, 2021)

teuchter said:


> It just moves energy that's outside the house, into the house. The outside air gets slightly colder and the water circulating in the heating inside the house gets warmer.
> 
> Although it's true they work by magic, they don't create any free energy.


If you had a mug of water at 50C and another mug of water at 30C and mixed them together you get water at 40C not 80C.

E2a: even with a heat recovery ventilation system the air coming back in is slightly cooler than the air in the room, it doesn't come in warmer.


----------



## Saul Goodman (Oct 20, 2021)

Sprocket. said:


> My neighbour who has heard one in use told me that particular model was similar to having a large electric air compressor constantly running.
> Nice in the middle of the night when surrounded by them I surmise.


Your neighbour is talking shite.


----------



## Saul Goodman (Oct 20, 2021)

teuchter said:


> Although it's true they work by magic.


No, they don't.


----------



## WouldBe (Oct 20, 2021)

Saul Goodman said:


> No, they don't.


Certainly not natural.


----------



## teuchter (Oct 21, 2021)

WouldBe said:


> If you had a mug of water at 50C and another mug of water at 30C and mixed them together you get water at 40C not 80C.
> 
> E2a: even with a heat recovery ventilation system the air coming back in is slightly cooler than the air in the room, it doesn't come in warmer.


Through the magic of a heat pump you can make the mug of water at 30c go down to 20c and the mug of water at 50c go up to something higher than that.

Just like your fridge moves heat from the inside of it to the outside of it, using heat pump magic.

A heat recovery ventilation system doesn't use a heat pump, just a heat exchanger. And the air coming back in is slightly cooler because the heat exchanger isn't 100% effective. But it also doesn't require any energy to be put into the system other than that used by the fans to physically move the air.

A heat pump does need external energy to do the work of moving heat energy from one location to another. But if this allows it to move more energy than it needs to do the work of moving... Then you get more great energy out of the system than the electrical energy you use to run it. It's not free energy because it's not come from thin air - it's just energy that was previously in a different location.


----------



## Sprocket. (Oct 21, 2021)

Saul Goodman said:


> Your neighbour is talking shite.


Maybe, but the post below mine from StoneRoad appears to agree with my shite talking neighbour, who works in building control for North Lincolnshire Council.


----------



## MrCurry (Oct 21, 2021)

WouldBe said:


> I'm still not convinced they actually work as they appear to be over unity devices. A heat exchanger can't amplify the temperature of something so the extra heat must come from the compressor but again it can't be over unity. The only way I can see it working without breaking the laws of physics is if the heat generated by compressing the gas is more efficient than using a heating element.


Although they may appear to be unproven new technology from the perspective of the U.K. market where they’ve been rare until now, in other places around the world heat pumps have been heating people’s homes for over 50 years.  They’ve been common in Sweden since the 1970s and are now the most mainstream choice.  If they didn’t “actually work”, I think people would have noticed by now.

They do work, as the electrical energy it takes to move heat energy from one place (outside) to another (inside) and release it is much less than the energy which creating that amount of heat directly from electrical heating would consume.


----------



## WouldBe (Oct 21, 2021)

teuchter said:


> Just like your fridge moves heat from the inside of it to the outside of it, using heat pump magic.


I don't see how air in a fridge at 5C can make the "radiator" at the back of the fridge run at 50-60C. The maths doesn't add up.


----------



## WouldBe (Oct 21, 2021)

MrCurry said:


> Although they may appear to be unproven new technology from the perspective of the U.K. market where they’ve been rare until now, in other places around the world heat pumps have been heating people’s homes for over 50 years.  They’ve been common in Sweden since the 1970s and are now the most mainstream choice.  If they didn’t “actually work”, I think people would have noticed by now.
> 
> They do work, as the electrical energy it takes to move heat energy from one place (outside) to another (inside) and release it is much less than the energy which creating that amount of heat directly from electrical heating would consume.


Sorry you've misunderstood. They do work but not how people think they work.

They can still produce the heat directly from electricity if the heat is produced more efficiently. Look at light bulbs, 60W for tungsten filament, 11W for compact fluorescent and 6-8W for LEDs for the same output.

And heat pumps may work well in Scandinavia as the houses have always been much better insulated than houses in the UK.


----------



## teuchter (Oct 21, 2021)

WouldBe said:


> I don't see how air in a fridge at 5C can make the "radiator" at the back of the fridge run at 50-60C. The maths doesn't add up.


Show us the maths that doesn't add up.


----------



## WouldBe (Oct 21, 2021)

teuchter said:


> Show us the maths that doesn't add up.


Really?

When you were a kid did you ever put your thumb over the end of a bike pump and pump operate it?

The end of the pump didn't get hot due to some mystical heat exchange, it got hot due to you compressing the gas in the pump.


----------



## MrCurry (Oct 21, 2021)

WouldBe said:


> Sorry you've misunderstood. They do work but not how people think they work.
> 
> They can still produce the heat directly from electricity if the heat is produced more efficiently. Look at light bulbs, 60W for tungsten filament, 11W for compact fluorescent and 6-8W for LEDs for the same output.
> 
> And heat pumps may work well in Scandinavia as the houses have always been much better insulated than houses in the UK.


Righto - you’re clearly quite an expert. I’ll leave you to it and hope, in due course, the rest of the world catches up with your advanced understanding of the technology


----------



## Saul Goodman (Oct 21, 2021)

Sprocket. said:


> Maybe, but the post below mine from StoneRoad appears to agree with my shite talking neighbour, who works in building control for North Lincolnshire Council.


I've heard more compressors than I could possibly remember. I've also heard my mate's heat pump compressor. It's a scroll compressor and it's almost silent, and certainly quieter than any piston compressor I've ever heard, so regardless of where he works, your neighbour is wrong.


> Ground Source Heat Pumps​Volume isn’t much associated with GSHPs, because of the lack of fan unit. However, people do still ask whether ground source heat pumps are noisy or silent. Indeed, there are components that make some noise, but this is always less than the noise of an air source heat pump.
> 
> Heat from the ground is more consistent, and therefore the power capacity of the compressor isn’t as high. The heat pump doesn’t need to operate at full throttle, and this keeps it quieter.
> 
> ...







__





						Are ground and air source heat pumps noisy? | IMS Heat Pumps
					

Heat Pump Installers




					www.imsheatpumps.co.uk
				




Most piston compressors operate above the noise level that would require ear protection (85dB>)







Example​Noise level (decibels)​Breathing10Whispering / rustling leaves20Quiet rural area30Library / bird calls40*Heat pump noise limit (MCS)**42*Conversation at home50Conversation in an office or restaurant60Vacuum cleaner70Alarm clock / dishwasher80









						Heat Pump Noise Levels: How Noisy Are They? - Evergreen Energy
					

There are different types of heat pumps and the volume of noise they make depends on each model. Find out how each heat pump sounds and more.




					www.evergreenenergy.co.uk


----------



## 2hats (Oct 21, 2021)

bluescreen said:


> I have a dumb question for people who have heat pumps: are they noisy? Do the neighbours find them noisy?


I've just spent a couple of months living in a place heated only by an air source heat pump system. I didn't notice the unit was running unless I was standing outside within a couple of metres of it. No louder than the fridge; less intrusive than the dishwasher.


WouldBe said:


> I don't see how air in a fridge at 5C can make the "radiator" at the back of the fridge run at 50-60C. The maths doesn't add up.


A heat pump does not create thermal energy. It just moves around thermal energy that already exists.

Before we leap into thermodynamics, try thinking in terms of 278K and 323K and thus using a unit of (electrical) energy to move a very small amount of (several units of thermal) energy from a vast warm object/volume to ever-so-slightly warm up a (relatively) minuscule object/volume.


----------



## teuchter (Oct 21, 2021)

WouldBe said:


> Really?
> 
> When you were a kid did you ever put your thumb over the end of a bike pump and pump operate it?
> 
> The end of the pump didn't get hot due to some mystical heat exchange, it got hot due to you compressing the gas in the pump.


If you want to understand how a heat pump works, you can look it up on the internet. The heat is moved from one location to another, not generated by the compressor, as several people people have now pointed out.


----------



## Saul Goodman (Oct 21, 2021)

WouldBe said:


> They can still produce the heat directly from electricity if the heat is produced more efficiently. Look at light bulbs, 60W for tungsten filament, 11W for compact fluorescent and 6-8W for LEDs for the same output.


All resistive element heating systems are by definition 100% efficient at converting electricity into heat. They all have a COP of 1.0. So for every watt of electricity you put into the system, you get 1 watt or 3.41 BTU of heat out. The only thing you can effect is how you distribute that heat.


----------



## teuchter (Oct 21, 2021)

Saul Goodman said:


> All resistive element heating *systems* are by definition 100% efficient at converting electricity into heat.


Not correct


----------



## Sprocket. (Oct 21, 2021)

Saul Goodman said:


> I've heard more compressors than I could possibly remember. I've also heard my mate's heat pump compressor. It's a scroll compressor and it's almost silent, and certainly quieter than any piston compressor I've ever heard, so regardless of where he works, your neighbour is wrong.
> 
> 
> 
> ...



Thanks for the information and post. I too have heard, installed and maintained many compressors over the last 48 years working as a mechanical maintenance engineer. I know how loud a small garage/workshop compressor can sound at two in the morning, I personally haven’t heard a heat pump so I can’t speak from personal experience. 
But I admit my neighbour is prone to slight exaggeration, he wears rigger boots and gloves, goggles and ear defenders when mowing is lawn.
I won’t be installing an heat pump for at least ten years as I have recently retired and only changed my gas fired combi-boiler last August.


----------



## what (Oct 21, 2021)

teuchter said:


> If you want to understand how a heat pump works, you can look it up on the internet. The heat is moved from one location to another, not generated by the compressor, as several people people have now pointed out.


Actually its a mixture of both.
Simple explanation here.




__





						Heat Pumps Explained | Worcester Bosch
					

View Worcester's Greenstar combi and system ground source heats pumps and view how they work



					www.worcester-bosch.co.uk


----------



## Saul Goodman (Oct 21, 2021)

teuchter said:


> Not correct


Quote the whole post, then explain why it isn't correct.


----------



## teuchter (Oct 21, 2021)

Saul Goodman said:


> Quote the whole post, then explain why it isn't correct.


It's pretty straightforward; if the system contains any moving parts like a fan, then a portion of the energy will be converted into mechanical energy rather than heat. Yes you will now try and claim that a "resistive element heating system" contains nothing other than resistive elements, but we all know that's just as true as saying an LED lighting system contains nothing other than LEDs.


----------



## Saul Goodman (Oct 21, 2021)

teuchter said:


> It's pretty straightforward;* if the system contains any moving parts like a fan*, then a portion of the energy will be converted into mechanical energy rather than heat. Yes you will now try and claim that a "resistive element heating system" contains nothing other than resistive elements, but we all know that's just as true as saying an LED lighting system contains nothing other than LEDs.


That falls under distributing the heat, which is why you deliberately omitted that part of the quote. 
Nice try but disingenuous at best.


----------



## teuchter (Oct 21, 2021)

Saul Goodman said:


> That falls under distributing the heat, which is why you deliberately omitted that part of the quote.
> Nice try but disingenuous at best.



Nope, you said



> All resistive element heating systems are by definition 100% efficient at converting electricity into heat. They all have a COP of 1.0. So for every watt of electricity you put into the system, you get 1 watt or 3.41 BTU of heat out. The only thing you can effect is how you distribute that heat.



You didn't say that distributing the heat would affect the effficiency, nor did you define whether this distribution occurs within or outside of the system whose efficiency you are describing. And in any case they system could include moving parts that do not affect the distribution of the heat.

An embarrassing blunder, and yet more proof that I am much more expert in engineering matters than you are.


----------



## Saul Goodman (Oct 21, 2021)

teuchter said:


> Nope, you said
> 
> 
> 
> ...


Nope, all it proves is that you're a dick


----------



## Crispy (Oct 21, 2021)

teuchter said:


> It's pretty straightforward; if the system contains any moving parts like a fan, then a portion of the energy will be converted into mechanical energy rather than heat.


Think about what happens to that mechanical energy.


----------



## WouldBe (Oct 21, 2021)

Saul Goodman said:


> Quote the whole post, then explain why it isn't correct.


Resistive heating can also produce light which isn't heat.


----------



## WouldBe (Oct 21, 2021)

what said:


> Actually its a mixture of both.
> Simple explanation here.
> 
> 
> ...


Thats well simplified and doesn't actually explain it. We have already agreed that heat exchangers don't boost the temperature. So if ground temp at an average of around 12C is high enough to evaporate the gas then it would need to be cooled below 12C to convert it back into a liquid. As room temp is around 21C the returning gas will be around the same temp and won't liquify. The only way to liquify it is to compress it which requires energy but you've alread done that to raise the temp to start with so doesn't make sense.


----------



## Cloo (Oct 21, 2021)

The house insulation is the killer for me.  We're a terrace with side return, no cavities to insulate, so to have a heat pump I expect we'd be external insulation layer on 3 walls and triple glazing. 5k doesn't even start to cover it  Would love to go for it otherwise.


----------



## what (Oct 21, 2021)

Ok this is standard vapour compression cycle of refrigeration machines. A heat pump is a refrigeration machine used in reverse if being used to heat a space. Link below gives it in more detail





__





						The Vapour Compression Cycle - Heat Pump Association
					






					www.heatpumps.org.uk


----------



## Saul Goodman (Oct 21, 2021)

WouldBe said:


> Thats well simplified and doesn't actually explain it. We have already agreed that heat exchangers don't boost the temperature. So if ground temp at an average of around 12C is high enough to evaporate the gas then it would need to be cooled below 12C to convert it back into a liquid. As room temp is around 21C the returning gas will be around the same temp and won't liquify. The only way to liquify it is to compress it which requires energy but you've alread done that to raise the temp to start with so doesn't make sense.


Try to think of it as trying to freeze the ground.


----------



## Crispy (Oct 21, 2021)

WouldBe said:


> Resistive heating can also produce light which isn't heat.


It becomes heat as soon as it hits something.


----------



## what (Oct 21, 2021)

WouldBe said:


> Thats well simplified and doesn't actually explain it. We have already agreed that heat exchangers don't boost the temperature. So if ground temp at an average of around 12C is high enough to evaporate the gas then it would need to be cooled below 12C to convert it back into a liquid. As room temp is around 21C the returning gas will be around the same temp and won't liquify. The only way to liquify it is to compress it which requires energy but you've alread done that to raise the temp to start with so doesn't make sense.


Forgot to hit reply. See reply a few above.


----------



## teuchter (Oct 21, 2021)

Crispy said:


> Think about what happens to that mechanical energy.


It will move some dust particles from the floor onto a shelf, thus being converted into potential energy rather than heat.


----------



## WouldBe (Oct 21, 2021)

Crispy said:


> It becomes heat as soon as it hits something.


IR would but visible light is less likely to.


----------



## WouldBe (Oct 21, 2021)

Saul Goodman said:


> Try to think of it as trying to freeze the ground.


I understand that but the raise in temperature is due to compressing the refrigerant which is done electrically and I'm not sure the temp of the air or ground is actually relevant.


----------



## Crispy (Oct 21, 2021)

teuchter said:


> It will move some dust particles from the floor onto a shelf, thus being converted into potential energy rather than heat.


Everyone be sure to brush any shelf dust onto the floor to recover the stored energy during cold weather.


----------



## teuchter (Oct 21, 2021)

WouldBe said:


> I understand that but the raise in temperature is due to compressing the refrigerant which is done electrically and I'm not sure the temp of the air or ground is actually relevant.


This is going to be the next "plane and conveyor belt", isn't it.


----------



## MrCurry (Oct 21, 2021)

For anyone interested in how these things actually work, this is what the ground source heat pump which heats my house has been doing today. The first graph shows the “supply line” (heating water which runs thru the radiator system to heat the house) and tap water tank temps.

The heating is done in pulses rather than continuously. More efficient that way apparently. Around midday the tap water temp was boosted up because it got too low. The supply line temps go up as outdoor temps drop and vice versa.

The second graph is the refrigerant circuit with ”brine in” being the temp of the fluid coming into the heat pump from the borehole and “brine out“ being the temp of the fluid the heat pump is sending back out to be recirculated through the hole to collect more heat. When the supply line is being boosted up, the brine out is running just 2-3C lower than the incoming brine temps, which are 8-10C mostly, except when a big amount of heat was being taken for the tapwater cycle when it drops further.

Obviously for an air source heat pump you don‘t have a brine circuit, but the principle is the same, a small temp drop from a large volume of air gets you enough heat to provide a large temp increase in a much smaller volume of heating water.


----------



## Leafster (Oct 21, 2021)

MrCurry said:


> For anyone interested in how these things actually work, this is what the ground source heat pump which heats my house has been doing today. The first graph shows the “supply line” (heating water which runs thru the radiator system to heat the house) and tap water tank temps.
> 
> The heating is done in pulses rather than continuously. More efficient that way apparently. Around midday the tap water temp was boosted up because it got too low. The supply line temps go up as outdoor temps drop and vice versa.
> 
> ...


So, if I've understood the graphs correctly, your heating appears to be on all the time but the temperature of the water to the radiators is lower than we might have with a gas boiler? 

The fact that it's on for longer allows it to maintain a stable comfortable room temperature even though the radiators don't ever get as hot as with a gas boiler?


----------



## MrCurry (Oct 21, 2021)

Leafster said:


> So, if I've understood the graphs correctly, your heating appears to be on all the time but the temperature of the water to the radiators is lower than we might have with a gas boiler?
> 
> The fact that it's on for longer allows it to maintain a stable comfortable room temperature even though the radiators don't ever get as hot as with a gas boiler?


I didn’t want to make that post any more complicated, but the heating supply runs fairly low as I have underfloor heating. It’s all configurable in any case and can be set to higher temps to suit radiator systems.  

In the context of swapping a gas boiler for a heat pump system you‘d need to set it up to feed the house heating the same or very similar temps otherwise your room temps would surely vary, unless the thermostats can even things out.


----------



## WouldBe (Oct 21, 2021)

MrCurry said:


> For anyone interested in how these things actually work, this is what the ground source heat pump which heats my house has been doing today. The first graph shows the “supply line” (heating water which runs thru the radiator system to heat the house) and tap water tank temps.
> 
> The heating is done in pulses rather than continuously. More efficient that way apparently. Around midday the tap water temp was boosted up because it got too low. The supply line temps go up as outdoor temps drop and vice versa.
> 
> ...


And there are times there where you are pumping warmer brine back into the ground than your getting back out.


----------



## WouldBe (Oct 21, 2021)

teuchter said:


> This is going to be the next "plane and conveyor belt", isn't it.


No it's not at least not for me. Gases including refrigerants follow Boyles? law. Where Pressure = Temp / Volume.

I don't see any Delta (i.e. change in temp) infront of the T component so starting temp would appear to be irrelevant.


----------



## Leafster (Oct 21, 2021)

MrCurry said:


> I didn’t want to make that post any more complicated, but the heating supply runs fairly low as I have underfloor heating. It’s all configurable in any case and can be set to higher temps to suit radiator systems.
> 
> In the context of swapping a gas boiler for a heat pump system you‘d need to set it up to feed the house heating the same or very similar temps otherwise your room temps would surely vary, unless the thermostats can even things out.


I wondered whether you might have underfloor heating (because of the lower supply line temperature and being on for longer)


----------



## MrCurry (Oct 21, 2021)

WouldBe said:


> And there are times there where you are pumping warmer brine back into the ground that your getting back out.


That’s because of the on/off heating cycle and the fact the heatpump is indoors.  

When the heatpump is on it‘s drawing heat from the brine and the brine output temp is lower. When the heatpump isn‘t heating the water, the flow of brine slows then stops and the output brine is briefly warmer because it’s just passed thru a warm indoors environment (where the heat pump is) compared with the brine which is coming in from outside.

As soon as the brine flow starts up the outgoing temps will be below the incoming.


----------



## WouldBe (Oct 21, 2021)

MrCurry said:


> That’s because of the on/off heating cycle and the fact the heatpump is indoors.
> 
> When the heatpump is on it‘s drawing heat from the brine and the brine output temp is lower. When the heatpump isn‘t heating the water, the flow of brine slows then stops and the output brine is briefly warmer because it’s just passed thru a warm indoors environment (where the heat pump is) compared with the brine which is coming in from outside.
> 
> As soon as the brine flow starts up the outgoing temps will be below the incoming.


The last 2 peaks seem to correspond to when the pump is running.


----------



## MrCurry (Oct 21, 2021)

WouldBe said:


> The last 2 peaks seem to correspond to when the pump is running.


You can’t see when the heatpump is running from what I posted before. i think you’re inferring it (wrongly) from the supply line temp, when you see it rising.

I’ve put all the traces on one graph, and added the “discharge pipe” temps, which is the internal intermediate step between the compressor output heat exchanger and the heating and hot water supplies. The discharge pipe output is mixed into the supply line and tapwater feeds with variable position valves, which is why the supply line is much lower, because the hotter “discharge pipe” water is being mixed in to raise the supply line.  This discharge pipe temp is where you see when the compressor runs, as soon as the discharge pipe temps start climbing the compressor just kicked in.

The vertical scale gets compressed due to the range of temperatures, but you can still see the peaks in the brine temp and each time the brine output temp rises to a peak it’s when the compressor has been off a while. As soon as the discharge pipe temps start to climb, the “brine out” temps drop, because that’s where the heat is coming from.


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## WouldBe (Oct 21, 2021)

MrCurry said:


> You can’t see when the heatpump is running from what I posted before. i think you’re inferring it (wrongly) from the supply line temp, when you see it rising.
> 
> I’ve put all the traces on one graph, and added the “discharge pipe” temps, which is the internal intermediate step between the compressor output heat exchanger and the heating and hot water supplies. The discharge pipe output is mixed into the supply line and tapwater feeds with variable position valves, which is why the supply line is much lower, because the hotter “discharge pipe” water is being mixed in to raise the supply line.  This discharge pipe temp is where you see when the compressor runs, as soon as the discharge pipe temps start climbing the compressor just kicked in.
> 
> ...


And yet the supply line and discharge line follow each other almost perfectly. So my previous statement still stands.


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## MrCurry (Oct 22, 2021)

WouldBe said:


> And yet the supply line and discharge line follow each other almost perfectly. So my previous statement still stands.


You said the last two peaks correspond to when the pump is running. They are actually directly before the pump starts up, as can be seen on the new graph.


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## Dogsauce (Oct 23, 2021)

Had a quick look on eBay for a cable percussion drilling rig to see if I could knock out a borehole in my tiny back yard for a ground source system, but sadly nothing there. It’s sandstone at 0.7m bgl so might take me a few years to get to 180m. Maybe a part-time hobby for me.

I’d actually be quite interested in an electric boiler as we don’t have a lot of outside wall space (we’re in a very deep terrace), so not needing to use some of this for the gas boiler would be a bonus.


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## MrCurry (Oct 23, 2021)

Dogsauce said:


> Had a quick look on eBay for a cable percussion drilling rig to see if I could knock out a borehole in my tiny back yard for a ground source system, but sadly nothing there. It’s sandstone at 0.7m bgl so might take me a few years to get to 180m. Maybe a part-time hobby for me.
> 
> I’d actually be quite interested in an electric boiler as we don’t have a lot of outside wall space (we’re in a very deep terrace), so not needing to use some of this for the gas boiler would be a bonus.


I’m not sure the authorities are too keen on people drilling their own boreholes in their back garden, probably some kind of permit is required to stop people puncturing gas mains / flooding tube tunnels / disturbing Maggie Thatcher in hell - that kinda thing.

The ground source systems come into their own in really cold ambient temps, which the U.K. doesn’t often get, so the cheaper to buy air source heat pumps are really a better option.


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