Air-source heat pumps - are they good/crap?
Discussion
Snow and Rocks said:
No direct experience of selling an ASHP equipped property but a friend is a conveyancing solicitor up here in Aberdeenshire and mentioned recently that she thinks heat pumps are still seen as a liability and potential source of grief rather an asset by most buyers.
Because they are very poor in the old housing stock and very cold weather, which is what the NE of Scotland is.Ours has been ultra reliable but is hellish expensive to run.
If it helps anyone understand it better, here are our energy usage stats from last year:
As I said earlier in the thread, the house was built with ashp in mind with UFH and has 25cm floor to roof external insulation with 30cm in the roof. For reference it’s 185m2.
Our total energy consumption last year was 3953kwh for heating and hot water. The house is always warm, we never turn it off except from April onwards when it’s more or less unnecessary to have central heating so I just turn off the heating and leave water only. In Austria we had between around -15 up to 40 last year. During winter it stays at between -5 and 5 degrees for weeks on end and it’s great to come home to a warm house without having that classic “let’s put the heating on”. Genuinely never think about it, the heat pump knows the outside temp and sets itself accordingly.
Electricity was expensive last year on our tariff so it was €0.28/kwh including network costs. So heating and HW cost around €1100 for the year. It’s now just gone down to total of €0.15/kwh or so with the new tariff. Therefore will be around €600 for the year. I can’t believe that I can heat and hw this house with gas to the same level for anywhere near that price.
I’m not trying to sell ashp but any of these scare stories you hear appear to be from poor understanding, or under-specced poor installations rather than actual problems with heat pumps themselves. So far ours has been flawless.
I think it would be hard to justify adding/retrofitting an ashp in a house which at didn’t have UFH at a minimum.
As I said earlier in the thread, the house was built with ashp in mind with UFH and has 25cm floor to roof external insulation with 30cm in the roof. For reference it’s 185m2.
Our total energy consumption last year was 3953kwh for heating and hot water. The house is always warm, we never turn it off except from April onwards when it’s more or less unnecessary to have central heating so I just turn off the heating and leave water only. In Austria we had between around -15 up to 40 last year. During winter it stays at between -5 and 5 degrees for weeks on end and it’s great to come home to a warm house without having that classic “let’s put the heating on”. Genuinely never think about it, the heat pump knows the outside temp and sets itself accordingly.
Electricity was expensive last year on our tariff so it was €0.28/kwh including network costs. So heating and HW cost around €1100 for the year. It’s now just gone down to total of €0.15/kwh or so with the new tariff. Therefore will be around €600 for the year. I can’t believe that I can heat and hw this house with gas to the same level for anywhere near that price.
I’m not trying to sell ashp but any of these scare stories you hear appear to be from poor understanding, or under-specced poor installations rather than actual problems with heat pumps themselves. So far ours has been flawless.
I think it would be hard to justify adding/retrofitting an ashp in a house which at didn’t have UFH at a minimum.
gareth h said:
Cheib said:
A quick look at utility bills will give you a pretty good idea how efficient a house. A lot of ASHP systems now have data logs so you can see how the system has been performing. The efficiency/effectiveness of an ASHP system is as much about flow rates, radiator size and how well the system has been set and and installed as it is about how air tight the house is.
Set up is a huge factor, I went to look at a mate’s daughter’s house last week, she’d had ASHP and solar installed foc under one of these grant schemes (in wales) , they were complaining about their electricity costs, there were a few issues, but the major one was the installer had just set the ASHP set point at 50 deg c and left, no setting weather compensation, no explaining how the system should work, a complete cowboy, taking government money and clearing off!For us we’ve got an old house which has a dog s
te single pipe central heating system so that’s being replaced with a twin pipe system of the correct capacity to support ASHP. Insulation, windows, external doors etc all being upgraded.I do feel like it’s riskier than going with a traditional gas boiler but we’ve got room for a large PV and Battery system so the most we’ll be paying 7.5p kWh (current Octopus tariff) for 95% of the year.
We have two. One for an annexe on our house with a separate electricity supply. And one for our outdoor pool that runs three or four months in the summer!
We’ve had issues, reliability being the main one. Annexe set up si from about 7 years ago, we had one failure under warranty, the supplier didn’t even bother to send an engineer to try to fix, just sent a new unit out. No local engineer was interested in the old unit even for parts and we gave it the scrap man! Installer put new unit in and back up and running pretty quick.
Sadly, then 4 years later, less than 5 years from original install, pump number 2 failed. Again, we struggled to find anyone to fix, one engineer from near 200 mile away said he may be able to come out next month, in the end we just prurchased a new pump, unrated version from same original supplier. I won’t go into too many more details as we’ve taken some action against, as they said they’d supply at cost plus x % and we subsequently found we could have just got it cheaper from another supplier.
It’s working ok, overall but it’s not great in the winter, tbh we’ve sort of stopped using the annexe in winter as a result. With no solar, I am convinced I winter it is noticeably more,pricey than gas we had before in there, but solar and tarrifs would help. I’d be surprised if our COP is over 3 average over the year.
And therein lies the successful side of our heat pump experience! The pool one is awesome, running it in the summer, the COP is 4 or 5, and packaging such that it is very efficient. We keep the outdoor pool at 31 degrees, really warm, and it’s a revaluation vs the old gas boiler, that seemed to either be way too hot or too cool. Not sure why, but it works great for a summer pool.
We have decided that when the annexe Hp fails as it no doubt will, we will link the underfloor heating into the main house gas CH gravity fed system and bin the HP.
That’s our experience. I’m sure some have fared better, and some worse. But I don’t think they suit older homes without serious work on insulation, doors, windows, draughts etc. they just don’t get the water hot enough to cope with very cold windy days one minute, and warmer days the next. Just not reactive enough, we have found.
But if you have a pool…..
We’ve had issues, reliability being the main one. Annexe set up si from about 7 years ago, we had one failure under warranty, the supplier didn’t even bother to send an engineer to try to fix, just sent a new unit out. No local engineer was interested in the old unit even for parts and we gave it the scrap man! Installer put new unit in and back up and running pretty quick.
Sadly, then 4 years later, less than 5 years from original install, pump number 2 failed. Again, we struggled to find anyone to fix, one engineer from near 200 mile away said he may be able to come out next month, in the end we just prurchased a new pump, unrated version from same original supplier. I won’t go into too many more details as we’ve taken some action against, as they said they’d supply at cost plus x % and we subsequently found we could have just got it cheaper from another supplier.
It’s working ok, overall but it’s not great in the winter, tbh we’ve sort of stopped using the annexe in winter as a result. With no solar, I am convinced I winter it is noticeably more,pricey than gas we had before in there, but solar and tarrifs would help. I’d be surprised if our COP is over 3 average over the year.
And therein lies the successful side of our heat pump experience! The pool one is awesome, running it in the summer, the COP is 4 or 5, and packaging such that it is very efficient. We keep the outdoor pool at 31 degrees, really warm, and it’s a revaluation vs the old gas boiler, that seemed to either be way too hot or too cool. Not sure why, but it works great for a summer pool.
We have decided that when the annexe Hp fails as it no doubt will, we will link the underfloor heating into the main house gas CH gravity fed system and bin the HP.
That’s our experience. I’m sure some have fared better, and some worse. But I don’t think they suit older homes without serious work on insulation, doors, windows, draughts etc. they just don’t get the water hot enough to cope with very cold windy days one minute, and warmer days the next. Just not reactive enough, we have found.
But if you have a pool…..
poo at Paul's said:
We have two. Again, we struggled to find anyone to fix, one engineer from near 200 mile away said he may be able to come out next month,
Highlighting a potential issue in the future - finding anyone to fix heat pumps.Fixed speed or inverter; sensors, refrigerant leaks, compressor seizure, boards, capacitors, heat exchange failure...been there, done that.
And it is rare for anything to be common between units, spare parts tend to be very specific.
It's also not an easy job to learn - and some jobs, such as changing a compressor, require a number of special tools.
poo at Paul's said:
And therein lies the successful side of our heat pump experience! The pool one is awesome, running it in the summer, the COP is 4 or 5, and packaging such that it is very efficient. We keep the outdoor pool at 31 degrees, really warm, and it’s a revaluation vs the old gas boiler, that seemed to either be way too hot or too cool. Not sure why, but it works great for a summer pool.
It takes heat from the air, I'm not surprised it works well at heating in summer!caziques said:
poo at Paul's said:
We have two. Again, we struggled to find anyone to fix, one engineer from near 200 mile away said he may be able to come out next month,
Highlighting a potential issue in the future - finding anyone to fix heat pumps.poo at Paul's said:
We have two. One for an annexe on our house with a separate electricity supply. And one for our outdoor pool that runs three or four months in the summer!
We’ve had issues, reliability being the main one. Annexe set up si from about 7 years ago, we had one failure under warranty, the supplier didn’t even bother to send an engineer to try to fix, just sent a new unit out. No local engineer was interested in the old unit even for parts and we gave it the scrap man! Installer put new unit in and back up and running pretty quick.
Sadly, then 4 years later, less than 5 years from original install, pump number 2 failed. Again, we struggled to find anyone to fix, one engineer from near 200 mile away said he may be able to come out next month, in the end we just prurchased a new pump, unrated version from same original supplier. I won’t go into too many more details as we’ve taken some action against, as they said they’d supply at cost plus x % and we subsequently found we could have just got it cheaper from another supplier.
It’s working ok, overall but it’s not great in the winter, tbh we’ve sort of stopped using the annexe in winter as a result. With no solar, I am convinced I winter it is noticeably more,pricey than gas we had before in there, but solar and tarrifs would help. I’d be surprised if our COP is over 3 average over the year.
And therein lies the successful side of our heat pump experience! The pool one is awesome, running it in the summer, the COP is 4 or 5, and packaging such that it is very efficient. We keep the outdoor pool at 31 degrees, really warm, and it’s a revaluation vs the old gas boiler, that seemed to either be way too hot or too cool. Not sure why, but it works great for a summer pool.
We have decided that when the annexe Hp fails as it no doubt will, we will link the underfloor heating into the main house gas CH gravity fed system and bin the HP.
That’s our experience. I’m sure some have fared better, and some worse. But I don’t think they suit older homes without serious work on insulation, doors, windows, draughts etc. they just don’t get the water hot enough to cope with very cold windy days one minute, and warmer days the next. Just not reactive enough, we have found.
But if you have a pool…..
Who was the manufacturer?, I’ve seen heat pumps at both ends of the spectrum, one imported from China by a boiler manufacturer that was very crude and suffered catastrophic failure a few years after install and several Daikin units that are very well manufactured and if maintained by them (an annual visit) are warranted for 5 years (I think possibly longer).We’ve had issues, reliability being the main one. Annexe set up si from about 7 years ago, we had one failure under warranty, the supplier didn’t even bother to send an engineer to try to fix, just sent a new unit out. No local engineer was interested in the old unit even for parts and we gave it the scrap man! Installer put new unit in and back up and running pretty quick.
Sadly, then 4 years later, less than 5 years from original install, pump number 2 failed. Again, we struggled to find anyone to fix, one engineer from near 200 mile away said he may be able to come out next month, in the end we just prurchased a new pump, unrated version from same original supplier. I won’t go into too many more details as we’ve taken some action against, as they said they’d supply at cost plus x % and we subsequently found we could have just got it cheaper from another supplier.
It’s working ok, overall but it’s not great in the winter, tbh we’ve sort of stopped using the annexe in winter as a result. With no solar, I am convinced I winter it is noticeably more,pricey than gas we had before in there, but solar and tarrifs would help. I’d be surprised if our COP is over 3 average over the year.
And therein lies the successful side of our heat pump experience! The pool one is awesome, running it in the summer, the COP is 4 or 5, and packaging such that it is very efficient. We keep the outdoor pool at 31 degrees, really warm, and it’s a revaluation vs the old gas boiler, that seemed to either be way too hot or too cool. Not sure why, but it works great for a summer pool.
We have decided that when the annexe Hp fails as it no doubt will, we will link the underfloor heating into the main house gas CH gravity fed system and bin the HP.
That’s our experience. I’m sure some have fared better, and some worse. But I don’t think they suit older homes without serious work on insulation, doors, windows, draughts etc. they just don’t get the water hot enough to cope with very cold windy days one minute, and warmer days the next. Just not reactive enough, we have found.
But if you have a pool…..
Choose carefully!
gareth h said:
Who was the manufacturer?, I’ve seen heat pumps at both ends of the spectrum, one imported from China by a boiler manufacturer that was very crude and suffered catastrophic failure a few years after install and several Daikin units that are very well manufactured and if maintained by them (an annual visit) are warranted for 5 years (I think possibly longer).
Choose carefully!
We’re looking at a Panasonic T-Cap which has a 7 year Warranty. High temperature heat pump, think 75 deg C from memory. Choose carefully!
We're 10 months in with our ASHP in a good size sprawling bungalow, highly insulated. A mixture of octopus cosy tariff (averages out to 22p/kwh from our usage) and an ASHP running at about 3.4COP gives us an energy cost of about 6.5p/kWh.
However.... The 300L cylinder and 52degree DHW is the negative, with a large household we do have to compromise on hot showers. I shower last and it's luke warm at times, and due to the peak rate between 4 and 7pm in our tariff I'm too stingy to pay to reheat it during that period. We have an insulated recirculation loop which draws the heat out as well.
However.... The 300L cylinder and 52degree DHW is the negative, with a large household we do have to compromise on hot showers. I shower last and it's luke warm at times, and due to the peak rate between 4 and 7pm in our tariff I'm too stingy to pay to reheat it during that period. We have an insulated recirculation loop which draws the heat out as well.
Andeh1 said:
However.... The 300L cylinder and 52degree DHW is the negative, with a large household we do have to compromise on hot showers. I shower last and it's luke warm at times, and due to the peak rate between 4 and 7pm in our tariff I'm too stingy to pay to reheat it during that period. We have an insulated recirculation loop which draws the heat out as well.
Hmmm, I wonder if the cylinder heating side of things is installed correctly, and I wonder if the circulating system has been done right.For example, the circulation return should be near the top of the cylinder, the water thermostat should be around 500mm from the bottom.
But is the cylinder heated via coils, or an external heat exchanger?
Coils can be a problem, they need to be much longer than standard when a heat pump is used. And what size heat pump?
Andeh1 said:
We're 10 months in with our ASHP in a good size sprawling bungalow, highly insulated. A mixture of octopus cosy tariff (averages out to 22p/kwh from our usage) and an ASHP running at about 3.4COP gives us an energy cost of about 6.5p/kWh.
However.... The 300L cylinder and 52degree DHW is the negative, with a large household we do have to compromise on hot showers. I shower last and it's luke warm at times, and due to the peak rate between 4 and 7pm in our tariff I'm too stingy to pay to reheat it during that period. We have an insulated recirculation loop which draws the heat out as well.
Is 52 deg all you can achieve or is the temperature that has been set? However.... The 300L cylinder and 52degree DHW is the negative, with a large household we do have to compromise on hot showers. I shower last and it's luke warm at times, and due to the peak rate between 4 and 7pm in our tariff I'm too stingy to pay to reheat it during that period. We have an insulated recirculation loop which draws the heat out as well.
We have just had a sales rep come to talk with us about an ASHP. Quite informative about some of the newer pumps providing much quicker response when heat required and a lot of guff about punitive taxes on gas in the future. However the cost was eye-watering - nearly £20K after the £7.5K gov grant for a five bed, fairly modern and well insulated timber framed house. Does this seem reasonable?
Beggarall said:
We have just had a sales rep come to talk with us about an ASHP. Quite informative about some of the newer pumps providing much quicker response when heat required and a lot of guff about punitive taxes on gas in the future. However the cost was eye-watering - nearly £20K after the £7.5K gov grant for a five bed, fairly modern and well insulated timber framed house. Does this seem reasonable?
How long would it take you to save £20k on heating?Beggarall said:
We have just had a sales rep come to talk with us about an ASHP. Quite informative about some of the newer pumps providing much quicker response when heat required and a lot of guff about punitive taxes on gas in the future. However the cost was eye-watering - nearly £20K after the £7.5K gov grant for a five bed, fairly modern and well insulated timber framed house. Does this seem reasonable?
Definitely taking the piss territory.Just do a basic add up of the cost of the parts, and, say £300 per man day labour. I reckon that after the cost of parts, that about 60 days installation time...................................
Its just another government sponsored bandwagon for the unscrupulous to prey on the gullible.
Edited to add, and you wont get any gurantee on running costs. Unless they are competent (unlikely) it will probably cost a fortune to run too. But that will be a problem you get to own afterwards.
Edited by monkfish1 on Wednesday 15th May 22:24
JuanCarlosFandango said:
How long would it take you to save £20k on heating?
Spending £20k to potentially save on potential taxes that may or may not happen at some indeterminate point in the future doesn't seem particularly wise financially.There's literally no downside to waiting. Prices will come down, the units will become (slightly) more efficient and you can avoid those potential tax increases if, and when they happen.
Beggarall said:
We have just had a sales rep come to talk with us about an ASHP. Quite informative about some of the newer pumps providing much quicker response when heat required and a lot of guff about punitive taxes on gas in the future. However the cost was eye-watering - nearly £20K after the £7.5K gov grant for a five bed, fairly modern and well insulated timber framed house. Does this seem reasonable?
It all depends on whats in the quote? Is that just for new a ASHP, and if so what make is it (some are a fair but more than others), does it include all new underfloor heating and a new hot water cylinder too? How big is the ASHP(s) they are suggesting? Its toppy for sure but its feasible if it includes many ot all the above items. You can very easily check the prices of the actual ASHP and cylinder online.
jonathan_roberts said:
I’m not trying to sell ashp but any of these scare stories you hear appear to be from poor understanding, or under-specced poor installations rather than actual problems with heat pumps themselves. So far ours has been flawless.
Actually your energy use in winter looks incredible compared to just our electricity usage just for the house+EV charging WITHOUT heating. That's with our house having a PowerWall and solar PV. I would say your experiences of overall energy usage is totally different from others (certainly mine). Add in energy needed for an ASHP versus gas, I suspect our electricity bill for winter would be double yours. You data simply confirms what I fear, ASHP only works if you build your house for it. I personally rather not build a house design around the heating source/bill.....
Better insultation however is the way to go regardless, the house use to visibly leak heat in winter, you could see bits of dust going up into cracks in the roof/celling when the heating was on full blast and it was freezing outside!! I'm hoping our rather extreme approach to improving insulation will mean heating bills for winter 2024 will be alot lower....The real irony is ofcourse global warming makes heating bills less worrying.....providing you don't live in a flood zone
.
We have an ASHP for our outdoor swimming pool too. Its a big Norsup unit and is very effective heating the water up (in tandem with 6.8kwh solar installation). I reckon it cost about £100 a month to heat a large pool to 30C (April-Oct).
In terms of reliability, the Norsup unit failed after 3 years and was not repairable. They replaced with a new unit under warranty.
In terms of reliability, the Norsup unit failed after 3 years and was not repairable. They replaced with a new unit under warranty.
AdamV12V said:
It all depends on whats in the quote? Is that just for new a ASHP, and if so what make is it (some are a fair but more than others), does it include all new underfloor heating and a new hot water cylinder too? How big is the ASHP(s) they are suggesting?
Its toppy for sure but its feasible if it includes many ot all the above items. You can very easily check the prices of the actual ASHP and cylinder online.
The quote was for a Hitachi Yukati -S80 High heat pump and a new water cylinder. No change in rads or UFH. Plus installation and an extra charge for the survey. Its toppy for sure but its feasible if it includes many ot all the above items. You can very easily check the prices of the actual ASHP and cylinder online.
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