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Thread: Air Source Heat Pumps

  1. #1

    Air Source Heat Pumps

    Evening All,

    Later this year we will be undertaking a full renovation of our property. As such it gives us a blank canvas as to what we install. One of the items for discussion is an Air source heat pump. Which could be used to remove the need for gas boilers. For a bit of background the house is approximately 5000sqft, most of the downstairs will be heated with underfloor heating. A few questions;

    Does anyone have one?

    How well do they perform? How hot is the water?

    What are the running/servicing costs like?

    What downsides are there?

    We are also looking at having solar panels installed to potentially power the heat pump, has anyone done this?

    All help greatly received.


    Kind Regards

  2. #2

    Air Source Heat Pumps

    Sorry, can’t help, but someone will be along shortly I am sure.

    Just in case you hadn’t thought of it, plenty of experience on YouTube, and seem to remember Skill Builder has some recent stuff on this.

    But some thoughts on this, and they may not be applicable to your situation as you are renovating from scratch so presume have the ability to add lots of insulation to the house.

    I am an engineer and have access to simulation software through work to model any process flow sheet, so used it to model and understand the air source heat pump process (basically the reverse of a refrigerant cycle).

    Really interesting results and I wanted to get my head around the whole thing from a theoretical point of view, rather than rely on anecdotes and experience, as I am looking at it as a possible future addition.

    With gas prices still 1/4 the price of leccy, and unlikely to get ever a COP of 4 or greater (which the model was good for) in winter when I need it, I have shelved any plans for now.

    My boiler and radiators will need changing in the next few years, so I will revisit then, especially as the reliability of the technology should improve and if the spread of gas to leccy price narrows.

    But, our house is old stock and difficult to upgrade the insulation, so it is always going to be a more difficult candidate for an ASHP.

    Just doesn’t make economic sense if you are getting significantly less than a COP of 3 in winter and the leccy costs 4 times the price of gas. Even with the £7,500 grant, and 90%+ gas boiler efficiency.

    Fine if you want to decarbonise your house with electrification, but usually you expect and economic reason to ease the decision, and an ASHP currently has no payback or rate of return, as it costs more to install and operate than a gas boiler, even with the grant. And the latter is much established and proven technology, whereas ASHP comes with a lot of challenges, most notably getting the set-up correct for the properties of the house. A gas boiler is very forgiving in this respect.
    Last edited by noTAGlove; 25th March 2024 at 00:04.

  3. #3
    Craftsman
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    Does anyone have one?

    I have a Mitsubishi Ecodan (UFH) fitted in a new build, constructed from SIP, tripple glazed and MVHR. You need to ensure that you improve the insulation and prevent any air leaks.

    How well do they perform? How hot is the water?

    It works very well, mine is in weather compensation mode with flow temperatures around 30C. Hot water is excellent, just like a gas boiler.

    What are the running/servicing costs

    I’ve not had mine serviced yet but expect the cost to be higher than a gas boiler (£250). Mitsubishi do service plans that also cover parts.

    What downsides are there?

    You need to get a proper heat survey done to get the sizing right (check out heat geeks on YouTube) and registered fitters seem rather thin on the ground. My current COP is around 2, not the 4 I would like but I’m very happy with the system.

    Finding a good fitter and the room needed to fit the kit inside. In winter the internal pump circulates water to prevent the air pump and pipes freezing (can be switched off) which causes some issues if placed in an old airing cupboard near bedrooms.

    We are also looking at having solar panels installed to potentially power the heat pump, has anyone done this?

    I’ve just fitted 11 solar panels (all I could fit) and two batteries so still in its infancy, the air source heat pump eats them up very quickly but overall I’m impressed.

  4. #4
    Grand Master thieuster's Avatar
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    A certified fitter who worked on our central heating was very clear that he wouldn’t install one in his own house for at least 5 years. They’re currently too expensive according to him.

    My inlaws have a hybrid natural gas/heat pump in their brand-new, super-insulated Dutch home, together with 30 solar panels on the roof. My FiL not impressed (disappointed) when it comes to the amount of gas he still needs to heat their bungalow.

    I guess that focussing on insulation and ventilation delivers more until the price of hp’s is down.

  5. #5

    Air Source Heat Pumps

    Quote Originally Posted by MonkeyBoy View Post
    My current COP is around 2, not the 4 I would like but I’m very happy with the system.
    This is the crux of the matter. Even with a gas boiler not achieving 100% efficiency, with a COP of 2 and leccy costing 4 times more than gas per kWh, utility bills are going to be double that of running a gas boiler. This will be a huge additional cost to the owner (think +£2k/yr)

    If the Goverment want mass take up of ASHP then they should invest to reduce the price of electricity (and more importantly the spread of gas to leccy price per kWh). The £7,500 grant is just a gimmick.

  6. #6
    Craftsman
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    Quote Originally Posted by noTAGlove View Post
    This is the crux of the matter. Even with a gas boiler not achieving 100% efficiency, with a COP of 2 and leccy costing 4 times more than gas per kWh, utility bills are going to be double that of running a gas boiler. This will be a huge additional cost to the owner (think +£2k/yr)

    If the Goverment want mass take up of ASHP then they should invest to reduce the price of electricity (and more importantly the spread of gas to leccy price per kWh). The £7,500 grant is just a gimmick.

    This is why I stressed that you get a proper heat survey done. The friend of a friend engineer did my calculation off a plan and massively over calculated by a factor of 2. With a properly sized heat pump I’m sure my COP would be nearer 4.

    However I would be the first to admit that heat pumps don’t suit all properties.

  7. #7
    Master
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    Quote Originally Posted by glyn696486 View Post
    Evening All,

    Later this year we will be undertaking a full renovation of our property. As such it gives us a blank canvas as to what we install. One of the items for discussion is an Air source heat pump. Which could be used to remove the need for gas boilers. For a bit of background the house is approximately 5000sqft, most of the downstairs will be heated with underfloor heating. A few questions;

    Does anyone have one?

    How well do they perform? How hot is the water?

    What are the running/servicing costs like?

    What downsides are there?

    We are also looking at having solar panels installed to potentially power the heat pump, has anyone done this?

    All help greatly received.


    Kind Regards
    we have one, works pretty well but it needs to be set up properly so you need a heating engineer not a regular plumber.

    If you have solar and you manage the use correctly (heat water at cheaper electricity rates etc) they can work out very well, annual servicing is around £250.

    Its a different mindset to a gas boiler tho so educate yourself, wealth of info on YT, also solar will make a difference (although your usage is highest when the solar produces the least)

  8. #8
    Master Thewatchbloke's Avatar
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    My dad had one installed in his 1960's bungalow in 2019, along with all the upgrades the system and bungalow needed to allow it to be fitted it seems to work very well, but energy costs are no cheaper than when he had an old oil fired boiler.

  9. #9

    Air Source Heat Pumps

    Quote Originally Posted by MonkeyBoy View Post
    With a properly sized heat pump I’m sure my COP would be nearer 4.
    You can’t change the laws of thermodynamics, and this is where people need to do their homework.

    With mid winter temperatures you are never going to get a COP much above 2.5 whatever system you install.

    COP of 4 is achievable in very mild conditions, and a time when you switch the heating off!

  10. #10
    I cannot comment on the heat pump. We are considering too, but the heating engineer I trust is sceptical of it would work for our house without spending a lot of money.


    Regarding solar, for us it has definitely been worth it, we had 18 panels and a 10 kwh battery installled. Like heat pumps you need a reputable installer who sources quality panels etc. My friend, who installed ours, gets about a quarter of his work from fixing poorly, and sometimes dangerously installed, set ups.

    Even at this time of year on a sunny day we are generating over 30kwh. With Octopus feed in tariffs our bill should be comfortably negative for the year, from previously paying 400 a month. Bonus with an ev is free mileage!


  11. #11

    Air Source Heat Pumps

    Quote Originally Posted by Matt8500 View Post
    Regarding solar, for us it has definitely been worth it
    Horses for courses and solar and batteries would be equivalent to burning £50 notes for me.

    80% of my electricity is now consumed at night (EV, tumble dryer, washing machine and dishwasher) at 9.5p/kWh between midnight and 7am, when compared to approx. 28p/kWh daytime rate at all other hours

    If you can shift your bulk electricity consumption to cheap overnight rates which almost all suppliers offer, none of these energy saving methods make any sense as you are into paybacks of low decades.

    The overnight electricity you are using typically comes from renewables anyway, so you are still using green energy.

    In fact, forget solar and harvest the overnight 9.5p/kWh into batteries if you still have significant daytime usage.

    All these utility companies benefit from massive economies of scale. How are you ever going to compete with your very expensive one-off home projects without massive government subsidies?

    It costs me less than £250 to charge my EV per year for 10k miles of use. Do I really want to put in £10k worth of solar and batteries in comparison?

    I think it is all a bit of a clever scam designed by the government to have the users load shed demand on the grid rather than the utilities companies provide it. It probably makes sense to balance the demand this way, but the users are given a false sense that somehow it is financially rewarding for the user to do it.

    And play it wrong and it will cost you, rather than save you money, with significant capital outlay and extremely low paybacks that any commercial company would not tolerate.
    Last edited by noTAGlove; 25th March 2024 at 12:55.

  12. #12
    I think you may need to look at your maths again as you are still paying for power… we also get 18p/kwh feed in all day, apart from 4-7pm where it is 30. The battery is set to charge at cheap rate at night and then use as needed during the day. Dumping excess at peak hours. I did a lot of investigation and conservative payback period is 6.5 years.

  13. #13

    Air Source Heat Pumps

    Quote Originally Posted by Matt8500 View Post
    I think you may need to look at your maths again as you are still paying for power… we also get 18p/kwh feed in all day, apart from 4-7pm where it is 30. The battery is set to charge at cheap rate at night and then use as needed during the day. Dumping excess at peak hours. I did a lot of investigation and conservative payback period is 6.5 years.
    What is the point of solar then? Even a small to medium size set up is £5k+.

    Just harvest in batteries at 9.5p/kWh overnight and sell back at 18/30p/kWh.
    As always do your maths very carefully and factor in very cheap overnight rates and shifting your bulk usage, as you may end up becoming a trader of electricity with fine margins when you factor in the significant cost of capital.

    I am not interested in becoming a trader as prices and the market is in continual flux and stacked against me.

    You will have noticed that batteries alone was my recommendation above, IF you can get this work financially. This can work if you can’t avoid significant and bulk daytime use. But, I can’t get anywhere near a tolerable breakeven point myself as 80% of my electricity is very cheap overnight rates. Solar is a scam IMO.

    Strange that utility companies don’t use batteries for storage (or very, very little) and store their cheap overnight power for expensive daytime sales, because it makes no economic sense for them to do so.
    Last edited by noTAGlove; 25th March 2024 at 13:21.

  14. #14
    Have you actually done the maths? You come across as just being down on solar without facts to back it up.

    The cost of the panels is relatively cheap, the battery is the expensive bit. We are generating up to just over 7 kw in the sun, and getting paid for what we are not using. With a busy family, and working from home, we also cannot restrict power usage to nighttime!

    Anyway, you have obviously made your mind up. For others I would suggest properly looking into it, as it depends on your roof aspect, the area available, as well as your use, and will work for some but not others.

  15. #15
    Master blackal's Avatar
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    Quote Originally Posted by Matt8500 View Post
    Have you actually done the maths? You come across as just being down on solar without facts to back it up.

    The cost of the panels is relatively cheap, the battery is the expensive bit. We are generating up to just over 7 kw in the sun, and getting paid for what we are not using. With a busy family, and working from home, we also cannot restrict power usage to nighttime!

    Anyway, you have obviously made your mind up. For others I would suggest properly looking into it, as it depends on your roof aspect, the area available, as well as your use, and will work for some but not others.

    Do you live in the Scilly Isles or Shetland Isles? (or somewhere inbetween)

    It makes a big difference, I suspect.

  16. #16
    Quote Originally Posted by Matt8500 View Post
    Have you actually done the maths? You come across as just being down on solar without facts to back it up.

    The cost of the panels is relatively cheap, the battery is the expensive bit. We are generating up to just over 7 kw in the sun, and getting paid for what we are not using. With a busy family, and working from home, we also cannot restrict power usage to nighttime!

    Anyway, you have obviously made your mind up. For others I would suggest properly looking into it, as it depends on your roof aspect, the area available, as well as your use, and will work for some but not others.
    4kW solar battery arrangement for approximately £12k (£5k battery, £1k inverter, £6k solar panels).

    A typical 4 kW solar system will generate 2850 kW per year in ideal conditions (Yorkshire - middle of the country). With leccy use at equivalent of 28p and feed in tariff at 18p (and a little at 30p), let's say 25p/kWh overall, the theoretical saving is £713 per year.

    Simple payback of 17 years. Arbitrage trading of cheap overnight leccy sold back to the grid in the morning will help this a little.

    Once I factor in buying 80% of my leccy at 9.5p/kWh, I am into multi-decade paybacks.

  17. #17

    Air Source Heat Pumps

    And without a £5k battery you at an outlay of £7k but mostly feeding in more at 18p/kWh than you can consume at 28p/kWh. Let’s say an average of 20p/kWh when you take some usage into account.

    Still a 12+ year payback.

  18. #18
    You have obviously made your mind up, but my actual experience of a real system differs. As I said it depends on where you are, your roof orientation, the kit you buy and your use.

    As one example we have generated 707kwh from 18 panels, since the 7th Jan, in pretty gloomy weather, at the worst time of year. Our dual fuel bill for Feb was -40 quid, when before we were paying an average 400, and that was a bad month for generation and we burnt a fair amount of gas. This was through using power at cheap tariffs and the system managing when to push power to the grid versus charging, as well as straight generation. The next 7 ish months will be much better.

    I am not an evangelist for solar, and solar is not for everyone, but a blanket ‘it is all a rip off’ is demonstrably not true.

  19. #19
    Quote Originally Posted by Matt8500 View Post
    You have obviously made your mind up, but my actual experience of a real system differs. As I said it depends on where you are, your roof orientation, the kit you buy and your use.

    As one example we have generated 707kwh from 18 panels, since the 7th Jan, in pretty gloomy weather, at the worst time of year. Our dual fuel bill for Feb was -40 quid, when before we were paying an average 400, and that was a bad month for generation and we burnt a fair amount of gas. This was through using power at cheap tariffs and the system managing when to push power to the grid versus charging, as well as straight generation. The next 7 ish months will be much better.

    I am not an evangelist for solar, and solar is not for everyone, but a blanket ‘it is all a rip off’ is demonstrably not true.
    Glad it seems to work for you. But I'd be interested in hearing annual savings rather than snippets of one to two months, and how much your installation cost.

    With 18 panels and 10 kW battery(?), you appear to have north of £20k of stuff by the time it is professionally installed. If that's the case I'd be looking for £3k to £3.5k savings every year, or around £300 pcm savings every month of the year.

    As mentioned, I can't justify anything like that when 80% of my electricity is at 9.5p/kWh. There just isn't enough I spend to touch the sides of £300 pcm savings.

    But glad it works for you.

    My general advice is still stands. Shift what electricity you can to very low overnight rates. Then do you maths on that basis you have maximised that shift.

  20. #20
    The install was 21K for roughly 7.5 kw potential, but that was as we went for in roof panels for looks rather than the normal install. Yes 10Kwh battery, but also the auto backup for power cuts (which we get annoyingly frequently).

    It’s not randomly picked months, it was last month- February which is one of the worst of the year, and the saving was over 400 quid. We are in the south so that helps, but the maths still add up to way more than your break point.

    Like I said I am no champion of solar, but if you’ve got a reasonable sized roof facing the right way it is at least worth doing the maths properly, taking into account usage and the tariffs available.

  21. #21
    Master
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    Quote Originally Posted by Matt8500 View Post
    The install was 21K for roughly 7.5 kw potential, but that was as we went for in roof panels for looks rather than the normal install. Yes 10Kwh battery, but also the auto backup for power cuts (which we get annoyingly frequently).

    It’s not randomly picked months, it was last month- February which is one of the worst of the year, and the saving was over 400 quid. We are in the south so that helps, but the maths still add up to way more than your break point.

    Like I said I am no champion of solar, but if you’ve got a reasonable sized roof facing the right way it is at least worth doing the maths properly, taking into account usage and the tariffs available.
    Do not go too far into this, once he has a view point he becomes as contrary as Mary to any logic.

    Rear of his house is I’m guessing north facing from the photos shared & plastic grass. So the front would work but perhaps neighbours frown on such things.

    I’ve evaluated the same process as you & can’t see where the issue lies, lots of neighbours done similar, so can’t just be my daftness here.

  22. #22
    Master blackal's Avatar
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    Okay, you want to play Secret Squirrel on your exact location, but FFS - don't state that location matters and then keep it secret at least what lattitude range you live in..............

  23. #23
    Quote Originally Posted by Matt8500 View Post
    The install was 21K for roughly 7.5 kw potential, but that was as we went for in roof panels for looks rather than the normal install. Yes 10Kwh battery, but also the auto backup for power cuts (which we get annoyingly frequently).

    It’s not randomly picked months, it was last month- February which is one of the worst of the year, and the saving was over 400 quid. We are in the south so that helps, but the maths still add up to way more than your break point.

    Like I said I am no champion of solar, but if you’ve got a reasonable sized roof facing the right way it is at least worth doing the maths properly, taking into account usage and the tariffs available.
    Sounds good. You can’t shift your major usage overnight, so what you have looks like a great set up.

    However long it takes to payback, you will be safe in the knowledge it will, and then will give you the benefits of free leccy thereafter.

  24. #24
    Master
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    One of my brothers is a heating engineer (he gets annoyed when I call him a plumber!) and he was very sceptical about heat pumps.

    He’s fitted a few to houses where the owners insisted (and paid) to have them fitted where they haven’t really worked because they didn’t do the recommended upgrades to the insulation and radiators before it would work properly.

    He’s now moved into a new build house that has a heat pump fitted, and it’s working really well.

    Heat pumps in the right house are great, in an older poorly insulated house they’re usually a disappointment, which was always his professional view.

  25. #25
    Master blackal's Avatar
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    Quote Originally Posted by Tooks View Post
    One of my brothers is a heating engineer (he gets annoyed when I call him a plumber!) and he was very sceptical about heat pumps.

    He’s fitted a few to houses where the owners insisted (and paid) to have them fitted where they haven’t really worked because they didn’t do the recommended upgrades to the insulation and radiators before it would work properly.

    He’s now moved into a new build house that has a heat pump fitted, and it’s working really well.

    Heat pumps in the right house are great, in an older poorly insulated house they’re usually a disappointment, which was always his professional view.
    Sounds like he wasn't a plumber, but not 'quite' an engineer either..............

    Like any heating system - the heating system has to match the heat loss of the building.

    Like any method - there are chancers who will convince you that their system is the dog's danglies.

    Before spaffing out ££thousands - you need either sound thermodynamics analysis, or at least an absolute comparable case - to make your mind up.

  26. #26

    Air Source Heat Pumps

    Quote Originally Posted by Tooks View Post
    One of my brothers is a heating engineer (he gets annoyed when I call him a plumber!) and he was very sceptical about heat pumps.

    He’s fitted a few to houses where the owners insisted (and paid) to have them fitted where they haven’t really worked because they didn’t do the recommended upgrades to the insulation and radiators before it would work properly.

    He’s now moved into a new build house that has a heat pump fitted, and it’s working really well.

    Heat pumps in the right house are great, in an older poorly insulated house they’re usually a disappointment, which was always his professional view.
    They are a disappointment in a poorly insulated house because the heat pump and radiator capacity has not been sized correctly. That can be sorted out with a proper appraisal and optimised installation.

    What is fixed and is immovable is the COP of a heat pump as this follows the laws of thermodynamics. COP of 2.5 in the mid winter months when you are flogging your heat pump leads to very expensive utility bills when compared with a gas boiler.

    You currently need a COP of 4 for it to breakeven on operating costs when compare with a gas boiler. But then you are only get a of COP 4 when is it 15 degC outside and you no longer need the heating on.

    Electricity is currently 4 times the cost of gas, and heat pump will become much more widespread if/when the cost difference reduces to 2.

    There is a reason Norway have heat pumps everywhere. Cheap electricity from hydroelectric power supplied by, and backing up renewables.

  27. #27
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    Quote Originally Posted by Matt8500 View Post
    The install was 21K for roughly 7.5 kw potential, but that was as we went for in roof panels for looks rather than the normal install. Yes 10Kwh battery, but also the auto backup for power cuts (which we get annoyingly frequently).

    It’s not randomly picked months, it was last month- February which is one of the worst of the year, and the saving was over 400 quid. We are in the south so that helps, but the maths still add up to way more than your break point.

    Like I said I am no champion of solar, but if you’ve got a reasonable sized roof facing the right way it is at least worth doing the maths properly, taking into account usage and the tariffs available.
    How long to recoup the £21k?
    When you look long into an abyss, the abyss looks long into you.........

  28. #28
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    Quote Originally Posted by blackal View Post
    Sounds like he wasn't a plumber, but not 'quite' an engineer either..............

    Like any heating system - the heating system has to match the heat loss of the building.

    Like any method - there are chancers who will convince you that their system is the dog's danglies.

    Before spaffing out ££thousands - you need either sound thermodynamics analysis, or at least an absolute comparable case - to make your mind up.
    Quote Originally Posted by noTAGlove View Post
    They are a disappointment in a poorly insulated house because the heat pump and radiator capacity has not been sized correctly. That can be sorted out with a proper appraisal and optimised installation.

    What is fixed and is immovable is the COP of a heat pump as this follows the laws of thermodynamics. COP of 2.5 in the mid winter months when you are flogging your heat pump leads to very expensive utility bills when compared with a gas boiler.

    You currently need a COP of 4 for it to breakeven on operating costs when compare with a gas boiler. But then you are only get a of COP 4 when is it 15 degC outside and you no longer need the heating on.

    Electricity is currently 4 times the cost of gas, and heat pump will become much more widespread if/when the cost difference reduces to 2.

    There is a reason Norway have heat pumps everywhere. Cheap electricity from hydroelectric power supplied by, and backing up renewables.
    In fairness, he knows this and was doing the calculations and only recommending a heat pump install if the associated improvements and installation was adhered to.

    I think you two and him are in complete agreement.

  29. #29
    Quote Originally Posted by blackal View Post
    Okay, you want to play Secret Squirrel on your exact location, but FFS - don't state that location matters and then keep it secret at least what lattitude range you live in..............
    It’s not secret, I said before… south of England! North Hampshire to be more specific. I don’t know the specific latitude, I am so sorry. What is your point? It works if it works for your house and location, and maybe not if you live in the Highlands of Scotland, surrounded by trees in the lea of a mountain, with a small roof area.

  30. #30

    Air Source Heat Pumps

    Quote Originally Posted by Tooks View Post
    In fairness, he knows this and was doing the calculations and only recommending a heat pump install if the associated improvements and installation was adhered to.

    I think you two and him are in complete agreement.
    I definitely wasn’t having a go at your brother. Sounds like a his customers won’t or don’t want to listen to his advice.

    Like putting a small gas boiler in a very large house.

    The trouble is unless the installers are very well qualified to undertake the heat loss calculations, the risk of undersizing is always present, and probably the biggest selection and installation issue. It feels like the industry is not fully established and still working the fundamentals out when it comes to older, draughty homes.

    Gas boilers have been installed for decades, have good rules of thumb for radiator requirements, and unlike ASHP are very forgiving as they run a much hotter temperatures.

  31. #31
    Quote Originally Posted by Chris_in_the_UK View Post
    How long to recoup the £21k?
    6.5 years being pretty conservative with tariff predictions. As said before it depends on location and roof aspect.

  32. #32
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    Quote Originally Posted by noTAGlove View Post
    I definitely wasn’t having a go at your brother. Sounds like a his customers won’t or don’t want to listen to his advice.

    Like putting a small gas boiler in a very large house.

    The trouble is unless the installers are very well qualified to undertake the heat loss calculations, the risk of undersizing is always present, and probably the biggest selection and installation issue.

    Gas boilers have been installed for decades, have good rules of thumb for radiator requirements, and unlike ASHP are very forgiving as they run a much hotter temperatures.
    Yes, absolutely. The people who’ve had them fitted have seen that they work a lot of the time, but as you say as soon as the weather/temps overwhelm the capacity of the install (as they haven’t done the associated insulation improvements or changed the radiators to ones more suited to the lower water temps) then they call him to complain the house isn’t warm enough, and it’s costing a fortune in electricity.

    I’d love one, but the 150 year old house I live in would require a lot of expensive work for it to take the place of the oil boiler we have. It is getting to the end of its life though, so need to make some decisions in the next couple of years.

  33. #33
    Quote Originally Posted by Mj2k View Post
    Do not go too far into this, once he has a view point he becomes as contrary as Mary to any logic.

    Rear of his house is I’m guessing north facing from the photos shared & plastic grass. So the front would work but perhaps neighbours frown on such things.

    I’ve evaluated the same process as you & can’t see where the issue lies, lots of neighbours done similar, so can’t just be my daftness here.
    You are very right, I don’t really care as the maths work for us (and I am reasonably sensible ), and his opinion is based on a belief rather than facts.

  34. #34
    Master blackal's Avatar
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    Quote Originally Posted by Matt8500 View Post
    It’s not secret, I said before… south of England! North Hampshire to be more specific. I don’t know the specific latitude, I am so sorry. What is your point? It works if it works for your house and location, and maybe not if you live in the Highlands of Scotland, surrounded by trees in the lea of a mountain, with a small roof area.
    Okay - I ain't seeing it. Is it in this thread?

    Your calculations might not work in the Scottish central belt either, in open ground..............

  35. #35
    Quote Originally Posted by blackal View Post
    Okay - I ain't seeing it. Is it in this thread?

    Your calculations might not work in the Scottish central belt either, in open ground..............
    Yes in this thread. Have I said any different regarding your location point? I do not understand what is hard about this? The case for solar is completely specific to an individual property, it would be insane in some and stupid not to in others (if you have the cash). It really is not that hard to get.

  36. #36

    Air Source Heat Pumps

    Quote Originally Posted by Matt8500 View Post
    6.5 years being pretty conservative with tariff predictions. As said before it depends on location and roof aspect.
    Is that literature/promotional information or based on your actual data?

    Interested to know as I have considered the option, couldn’t get it to work and would like to hear other peoples numbers. But, feel free to duck out if it pushes you too far.

    A 8kW solar system generates around 7,000 kW of electricity per year.

    £21k on 6.5 year payback is £3,230 savings per year.

    Therefore each kW saved has to have a value of 3230/7000x100 = 46p

    With purchase tariff of 28p, base feed in tariff of 18p (30p for 3 hours per day), it does feel a stretch.

  37. #37
    Master blackal's Avatar
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    Quote Originally Posted by Matt8500 View Post
    Yes in this thread. Have I said any different regarding your location point? I do not understand what is hard about this? The case for solar is completely specific to an individual property, it would be insane in some and stupid not to in others (if you have the cash). It really is not that hard to get.
    Are we talking at cross purposes?

    I don't think you ever stated where you lived (until late on)

    You stated that it matters where you live. (no contention)

    Please show me where you stated you lived in southern England - to maintain my sanity, cos I am not seeing it prior to a few posts ago, and certainly not before I asked.

  38. #38
    Quote Originally Posted by blackal View Post
    Are we talking at cross purposes?

    I don't think you ever stated where you lived (until late on)

    You stated that it matters where you live. (no contention)

    Please show me where you stated you lived in southern England - to maintain my sanity, cos I am not seeing it prior to a few posts ago, and certainly not before I asked.
    Literally 2 posts before you asked. I fail to see what point you are making anyway, it works for us, and sounds like it would not for you.

  39. #39
    Master blackal's Avatar
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    Quote Originally Posted by Matt8500 View Post
    Literally 2 posts before you asked. I fail to see what point you are making anyway, it works for us, and sounds like it would not for you.

    Post a link to it, will you please - because I’m missing it. (Even going back through the thread).

    THe point I am making is that you posted several references about how ASHP was working for you, acknowledging (eventually) that it was dependant upon where you lived- without seemingly qualifying it with ….. where you live.

    I’m not doubting your satisfaction on the merits of ASHP - but it does require qualification, to be any use to people.

    Jimmy Smitts could make a similar case, without saying that he lived in South Africa.


    [edit; Ah, yes you did mention it - you said ‘the south’……. Aye - clever! ]
    Last edited by blackal; 25th March 2024 at 22:05.

  40. #40

    Air Source Heat Pumps

    If you cannot find it, that is not my problem. Sorry OP, I take partial blame for derailing this thread, I am out but still interested to read about heat pumps.

    Edit to say, are you ok, I was not even been posting about ASHPs?
    Last edited by Matt8500; 25th March 2024 at 22:07.

  41. #41
    Master blackal's Avatar
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    Quote Originally Posted by Matt8500 View Post
    If you cannot find it, that is not my problem. Sorry OP, I take partial blame for derailing this thread, I am out but still interested to read about heat pumps.
    At least you’ve stopped adding !!!s into your posts………..

  42. #42
    Quote Originally Posted by blackal View Post
    At least you’ve stopped adding !!!s into your posts………..
    Eh? I do not use excessive punctuation. It is either Tapatalk, or you are just argumentative. Either way I am out now.

  43. #43

    Air Source Heat Pumps

    Quote Originally Posted by Matt8500 View Post
    If you cannot find it, that is not my problem. Sorry OP, I take partial blame for derailing this thread, I am out but still interested to read about heat pumps.

    Edit to say, are you ok, I was not even been posting about ASHPs?
    I was hoping for more before you left. Nothing in your argument or information demonstrates a good economic reason to install solar and batteries.

    You said you can’t use overnight electricity, but you also have an EV? This will be the bulk of your household electricity consumption if you drive any miles.

    And I think this is useful information for anyone on the forum considering it, including myself.

    You can’t tell us how great it is without standing up to a little bit of scrutiny.
    Last edited by noTAGlove; 25th March 2024 at 22:17.

  44. #44
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    Quote Originally Posted by blackal View Post
    Post a link to it, will you please - because I’m missing it. (Even going back through the thread).

    THe point I am making is that you posted several references about how ASHP was working for you, acknowledging (eventually) that it was dependant upon where you lived- without seemingly qualifying it with ….. where you live.

    I’m not doubting your satisfaction on the merits of ASHP - but it does require qualification, to be any use to people.

    Jimmy Smitts could make a similar case, without saying that he lived in South Africa.


    [edit; Ah, yes you did mention it - you said ‘the south’……. Aye - clever! ]
    in fairness his posts were regarding solar not the ASHP.

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