Air Source Heat Pumps
Discussion
I have a friend who works for a large housing association. They have installed 20 air source heat pumps and complete new systems consisting of radiators and un vented cylinders as a trial scheme.
It’s his job to monitor these and calculate the exact running costs, he says at best they are just about comparable to natural gas running costs but these houses have had their systems designed from scratch and are well insulated.
If you have access to natural gas I’d be sticking with that,
Good luck
Ss
Very timely reading as I am supposed to be talking to a Vaillant installer at this moment, but he cancelled for the second time.
We have an 11kW LPG boiler for our house in France, where we live April to end of October, but are paying €2000 for the gas.
But if I have to change all the rads and run it 24/7 then I am really not interested.
I already have a 3kW ASHP to heat the pool in summer and I can’t say that I am overly impressed with that. But then I have not tried an alternative, either.
We have an 11kW LPG boiler for our house in France, where we live April to end of October, but are paying €2000 for the gas.
But if I have to change all the rads and run it 24/7 then I am really not interested.
I already have a 3kW ASHP to heat the pool in summer and I can’t say that I am overly impressed with that. But then I have not tried an alternative, either.
silversurfer1 said:
... he says at best they are just about comparable to natural gas running costs but these houses have had their systems designed from scratch and are well insulated.
We did a similar trial on the affordable housing on a large housing development that we built to (now defunct) Code for Sustainable Homes Level 4, and came to the same conclusion.... and that's a best-case scenario, on properties with high occupancy levels.
Heat pumps are not very responsive at dealing with sudden changes in demand, and we had endless complaints on open market properties (and those affordable units occupied by people who went out to work) of high running costs and poor flexibility, where people expected the system to tick over at night and through the day, but ramp up the internal temperature quickly in the morning and early evening.
They have their place, but I am extremely cautious about specifying ASHP, unless no better alternative is available and I have thoroughly discussed their shortcomings with the client.
Equus said:
We did a similar trial on the affordable housing on a large housing development that we built to (now defunct) Code for Sustainable Homes Level 4, and came to the same conclusion.
... and that's a best-case scenario, on properties with high occupancy levels.
Heat pumps are not very responsive at dealing with sudden changes in demand, and we had endless complaints on open market properties (and those affordable units occupied by people who went out to work) of high running costs and poor flexibility, where people expected the system to tick over at night and through the day, but ramp up the internal temperature quickly in the morning and early evening.
They have their place, but I am extremely cautious about specifying ASHP, unless no better alternative is available and I have thoroughly discussed their shortcomings with the client.
THIS^^... and that's a best-case scenario, on properties with high occupancy levels.
Heat pumps are not very responsive at dealing with sudden changes in demand, and we had endless complaints on open market properties (and those affordable units occupied by people who went out to work) of high running costs and poor flexibility, where people expected the system to tick over at night and through the day, but ramp up the internal temperature quickly in the morning and early evening.
They have their place, but I am extremely cautious about specifying ASHP, unless no better alternative is available and I have thoroughly discussed their shortcomings with the client.
ASHP are NOT very responsive to "on for an hour off for 8, on for 5 etc. but not as bad as many make out. You leave them on all the time, as the day warms up the controllers stop the pump, it comes on if you want hot water and again when the temps drop in the evening. Treating them like an old fashioned gas/oil etc system is wrong.
You also need slightly larger radiators (or more) than for gas/oil etc.
Two months in, we are happy with our set up, retro fitted into a 20 year old timber framed, reasonably well insulate 4 bed bungalow. We're reading the meter regularly and costs are less than for the problematic uncontrollable electric storage radiators previously installed and less than oil/lpg running costs. The heat generated is a more pleasant heat than storage radiators (difficult to describe sorry).
Our only problem so far is that with the wireless temp controller in the living areas which face south, the temp there is correct or higher than required so it switches off and the main bedroom which faces north and rarely gets any sun ends up a little cool. Moving the controller to the bedroom late in the day solves this (if you remember to do it).
Our installer has done a number of housing assoc developments as well as numerous single installations both new build and retro fit. Retro fit is the harder as you need to make sure the insulation, windows etc are up to scratch first.
For us with a £10k interest free loan, which we pay back over 7 years with the RHI payments and the prospective of lower energy bills and better control of the heating compared to 20 year old storage radiators, it is worthwhile for an upfront cost of £4910. A simple oil/LPG install would have been more than that.
Trying to get my wife to understand that you leave it on throughout the year and if you need a bit of warmth on a cooler summer evening it'll come on automatically as the temperature drops and you won't need a sudden boost of warmth from an additional fire/stove etc is more difficult. We'll see how things progress but so far I'm happy.
If anyone wants a recommendation for an installer on the west coast of Scotland (Oban and surrounding inc islands) drop me a line.
We are on our second ASHP, the first installed in 2007 gave up the ghost last year and we replaced it with a Vaillant 11kW aroTHERM. We do not have gas in our village and wanted to move away from oil whilst renovating the house. We have UFH downstairs and radiators upstairs and the system works very well for us. The house is always comfortable and we have plenty of hot water. The house is detached four bed, three bathroom mixed age property that is very well insulated. Four adults in and out the house all day and night. Currently paying £150 a month for electricity but expecting that to fall as we installed a 5kW Solar PV system last year.
I understand the general mechanics of how to get the best out of an ASHP.
I guess my problem is we've already renovated most of our house in the time we've owned it. As such, whilst I'd like underfloor heating downstairs, it would be cost prohibitive (not to mention massively disruptive) to dig up the floors to include this now. Which leaves us needing to uprate pretty much all of our rads. Given the number of rads in our house, we're looking at circa £4k for that alone based on the one estimate I've received thus far (still waiting on two more to come back). That's before we take into account the cost and disruption of installing a new hot water tank, ASHP, controllers etc.
That's a heck of a chunk of change for an 'invisible' benefit as my wife puts it. Whilst in time we'll obviously replace rads on a piecemeal basis anyway, we can spread the cost out for that, and I can largely do it myself, so nowhere near as painful taking the hit at one time.
If the benefit from ASHP was so significant vs the oil that we're otherwise running I'd probably feel like it was much more of an investment worth making, but I just don't get the sense that the return is secure enough to justify the outlay. Nothing much in this thread is so far making me feel differently either.
I guess my problem is we've already renovated most of our house in the time we've owned it. As such, whilst I'd like underfloor heating downstairs, it would be cost prohibitive (not to mention massively disruptive) to dig up the floors to include this now. Which leaves us needing to uprate pretty much all of our rads. Given the number of rads in our house, we're looking at circa £4k for that alone based on the one estimate I've received thus far (still waiting on two more to come back). That's before we take into account the cost and disruption of installing a new hot water tank, ASHP, controllers etc.
That's a heck of a chunk of change for an 'invisible' benefit as my wife puts it. Whilst in time we'll obviously replace rads on a piecemeal basis anyway, we can spread the cost out for that, and I can largely do it myself, so nowhere near as painful taking the hit at one time.
If the benefit from ASHP was so significant vs the oil that we're otherwise running I'd probably feel like it was much more of an investment worth making, but I just don't get the sense that the return is secure enough to justify the outlay. Nothing much in this thread is so far making me feel differently either.
Venom said:
I understand the general mechanics of how to get the best out of an ASHP.
I guess my problem is we've already renovated most of our house in the time we've owned it. As such, whilst I'd like underfloor heating downstairs, it would be cost prohibitive (not to mention massively disruptive) to dig up the floors to include this now. Which leaves us needing to uprate pretty much all of our rads. Given the number of rads in our house, we're looking at circa £4k for that alone based on the one estimate I've received thus far (still waiting on two more to come back). That's before we take into account the cost and disruption of installing a new hot water tank, ASHP, controllers etc.
That's a heck of a chunk of change for an 'invisible' benefit as my wife puts it. Whilst in time we'll obviously replace rads on a piecemeal basis anyway, we can spread the cost out for that, and I can largely do it myself, so nowhere near as painful taking the hit at one time.
If the benefit from ASHP was so significant vs the oil that we're otherwise running I'd probably feel like it was much more of an investment worth making, but I just don't get the sense that the return is secure enough to justify the outlay. Nothing much in this thread is so far making me feel differently either.
I think in your case I would agree with your thoughts. The running costs are not that different to our old oil CH and if we had not been doing a full house renovation I do not think an ASHP would have come into our thoughts......as a standalone solution I think it can be difficult to justify from a financial perspective. As part of a whole house solution they do work, if done properly, very well in our experience.I guess my problem is we've already renovated most of our house in the time we've owned it. As such, whilst I'd like underfloor heating downstairs, it would be cost prohibitive (not to mention massively disruptive) to dig up the floors to include this now. Which leaves us needing to uprate pretty much all of our rads. Given the number of rads in our house, we're looking at circa £4k for that alone based on the one estimate I've received thus far (still waiting on two more to come back). That's before we take into account the cost and disruption of installing a new hot water tank, ASHP, controllers etc.
That's a heck of a chunk of change for an 'invisible' benefit as my wife puts it. Whilst in time we'll obviously replace rads on a piecemeal basis anyway, we can spread the cost out for that, and I can largely do it myself, so nowhere near as painful taking the hit at one time.
If the benefit from ASHP was so significant vs the oil that we're otherwise running I'd probably feel like it was much more of an investment worth making, but I just don't get the sense that the return is secure enough to justify the outlay. Nothing much in this thread is so far making me feel differently either.
I'm about to embark on a self-build project and the issue of renewable heating/energy sources is on my mind.
My plot does not have mains gas but my opinion at the moment is still to go for a traditional heating solution (probably oil). My reasoning is thus: cheaper initial cost, proven technology, readily available service/maintenance professionals, running costs will not be too high in a well-insulated, air-tight, new build. I might add a wood burning stove to help with SAP calculations, and because I like them, but won't expect it to be a core part of the heating system.
As for ASHPs, I haven't really seen a compelling argument for them. The size, noise and electricity consumption all put me off. Plus I live in Scotland so temps will regularly be below 10C.
In summary, I'll probably go for an oil-fired system boiler because I think it's the most cost-effective and reliable solution in a new build.
Having said that, I'm open to be convinced otherwise...
My plot does not have mains gas but my opinion at the moment is still to go for a traditional heating solution (probably oil). My reasoning is thus: cheaper initial cost, proven technology, readily available service/maintenance professionals, running costs will not be too high in a well-insulated, air-tight, new build. I might add a wood burning stove to help with SAP calculations, and because I like them, but won't expect it to be a core part of the heating system.
As for ASHPs, I haven't really seen a compelling argument for them. The size, noise and electricity consumption all put me off. Plus I live in Scotland so temps will regularly be below 10C.
In summary, I'll probably go for an oil-fired system boiler because I think it's the most cost-effective and reliable solution in a new build.
Having said that, I'm open to be convinced otherwise...
mcbook said:
In summary, I'll probably go for an oil-fired system boiler because I think it's the most cost-effective and reliable solution in a new build.
Having said that, I'm open to be convinced otherwise...
Heat pumps are everywhere in Sweden and have been for years.Having said that, I'm open to be convinced otherwise...
They are tried and proven in cold environments.
Where they don't work is poor retrofits (old radiators, poor insulation, poor air tightness) and when compared directly against gas for cost.
If you're going new build then you can address all those issues.
shady lee said:
Upsize some rads to double convectors and turn your boilers flow temp down to 60c so it's in condensing mode for all of the year.
Over insulate the loft. Savings can be had, but the ashp outlay Vs reward just seems expensive.
Ha, yeah. I saw the comment that the government is planning to stop building houses with gas heating by like 2025 or something, which would be awesome if done right, but currently we are still miles behind on the low hanging fruit like really good insulation even on new builds. Get that right and it doesnt matter than you heat pump isnt good at being reactive, we only want to do 3 hours on 8hours of 5hours in the evening is because the heat is falling out of the house so fast that helps. if its well insulated, having it warm all day works!Over insulate the loft. Savings can be had, but the ashp outlay Vs reward just seems expensive.
I couldn't imagine anything worse than the noise of an ASHP, and as mentioned above believe it all falls apart in the UK where it can be sub-zero for weeks at a time even if this winter (2019) was quiet mild. My uncle has a whole house ground source heat pump and I keep meaning to talk to him in detail about how that is going, But it was rolled in with a whole house refurbishment including a mad amount of insulation, underfloor heating and large radiators. Obviously with GSHP you have the cost of the borehole, but otherwise its much better in terms of noise and heating when you need it as I understand.
Daniel
mcbook said:
I'm about to embark on a self-build project and the issue of renewable heating/energy sources is on my mind.
...
As for ASHPs, I haven't really seen a compelling argument for them. The size, noise and electricity consumption all put me off. Plus I live in Scotland so temps will regularly be below 10C.
In summary, I'll probably go for an oil-fired system boiler because I think it's the most cost-effective and reliable solution in a new build.
Having said that, I'm open to be convinced otherwise...
Have you looked into the Home Energy Scotland loan at all? Interest free chunks of money available to finance the installations. RHI then goes a long way to paying that off....
As for ASHPs, I haven't really seen a compelling argument for them. The size, noise and electricity consumption all put me off. Plus I live in Scotland so temps will regularly be below 10C.
In summary, I'll probably go for an oil-fired system boiler because I think it's the most cost-effective and reliable solution in a new build.
Having said that, I'm open to be convinced otherwise...
dhutch said:
I couldn't imagine anything worse than the noise of an ASHP, and as mentioned above believe it all falls apart in the UK where it can be sub-zero for weeks at a time even if this winter (2019) was quiet mild.
What are you on about? Heat pumps are used widely in Scandinavian countries that get, and stay, far colder than the UK mainland.Also, what noise? Short of having it literally outside your ground floor bedroom, I don't think you're going to hear it. Apartments around the world have Air Con units in or near the windows.
Evanivitch said:
What are you on about? Heat pumps are used widely in Scandinavian countries that get, and stay, far colder than the UK mainland.
Also, what noise? Short of having it literally outside your ground floor bedroom, I don't think you're going to hear it. Apartments around the world have Air Con units in or near the windows.
Do they? ASHP in Scandinavian?Also, what noise? Short of having it literally outside your ground floor bedroom, I don't think you're going to hear it. Apartments around the world have Air Con units in or near the windows.
In no expert but we had them at work and while they where fine for a office and in a house you have wet rads not blowers, the units outside got a right howl on when the outside temp dropped. And on got days of using air con.
Daniel
dhutch said:
Do they? ASHP in Scandinavian?
In no expert but we had them at work and while they where fine for a office and in a house you have wet rads not blowers, the units outside got a right howl on when the outside temp dropped. And on got days of using air con.
Daniel
Yes, ASHP in Sweden and the like. ASHP can also be used with wet systems, which is why they're usually used with underfloor heating. UFH uses a lower temperature, but a larger area to work efficiently. But it makes retrofit of ASHP more expensive and disruptive.In no expert but we had them at work and while they where fine for a office and in a house you have wet rads not blowers, the units outside got a right howl on when the outside temp dropped. And on got days of using air con.
Daniel
Your office ASHP are unlikely to place noise as high on their priorities. Just like a van often has a less refined engine than a car. But quieter products for domestic installation are common.
Jambo85 said:
mcbook said:
I'm about to embark on a self-build project and the issue of renewable heating/energy sources is on my mind.
...
As for ASHPs, I haven't really seen a compelling argument for them. The size, noise and electricity consumption all put me off. Plus I live in Scotland so temps will regularly be below 10C.
In summary, I'll probably go for an oil-fired system boiler because I think it's the most cost-effective and reliable solution in a new build.
Having said that, I'm open to be convinced otherwise...
Have you looked into the Home Energy Scotland loan at all? Interest free chunks of money available to finance the installations. RHI then goes a long way to paying that off....
As for ASHPs, I haven't really seen a compelling argument for them. The size, noise and electricity consumption all put me off. Plus I live in Scotland so temps will regularly be below 10C.
In summary, I'll probably go for an oil-fired system boiler because I think it's the most cost-effective and reliable solution in a new build.
Having said that, I'm open to be convinced otherwise...
(And we are in Scotland of course although the warmer bit (Oban)).
And re the noise issue, I can sometimes hear next doors ASHP but rarely our own which is pretty much silent. 11KW Nibe unit
Edited by Skyedriver on Thursday 11th April 18:42
Evanivitch said:
dhutch said:
Do they? ASHP in Scandinavian?
In no expert but we had them at work and while they where fine for a office and in a house you have wet rads not blowers, the units outside got a right howl on when the outside temp dropped. And on got days of using air con.
Daniel
Yes, ASHP in Sweden and the like. ASHP can also be used with wet systems, which is why they're usually used with underfloor heating. UFH uses a lower temperature, but a larger area to work efficiently. But it makes retrofit of ASHP more expensive and disruptive.In no expert but we had them at work and while they where fine for a office and in a house you have wet rads not blowers, the units outside got a right howl on when the outside temp dropped. And on got days of using air con.
Daniel
Your office ASHP are unlikely to place noise as high on their priorities. Just like a van often has a less refined engine than a car. But quieter products for domestic installation are common.
Skyedriver said:
Jambo85 said:
mcbook said:
I'm about to embark on a self-build project and the issue of renewable heating/energy sources is on my mind.
...
As for ASHPs, I haven't really seen a compelling argument for them. The size, noise and electricity consumption all put me off. Plus I live in Scotland so temps will regularly be below 10C.
In summary, I'll probably go for an oil-fired system boiler because I think it's the most cost-effective and reliable solution in a new build.
Having said that, I'm open to be convinced otherwise...
Have you looked into the Home Energy Scotland loan at all? Interest free chunks of money available to finance the installations. RHI then goes a long way to paying that off....
As for ASHPs, I haven't really seen a compelling argument for them. The size, noise and electricity consumption all put me off. Plus I live in Scotland so temps will regularly be below 10C.
In summary, I'll probably go for an oil-fired system boiler because I think it's the most cost-effective and reliable solution in a new build.
Having said that, I'm open to be convinced otherwise...
(And we are in Scotland of course although the warmer bit (Oban)).
And re the noise issue, I can sometimes hear next doors ASHP but rarely our own which is pretty much silent. 11KW Nibe unit
Edited by Skyedriver on Thursday 11th April 18:42
As has been said if you are doing a full renovation with UFH, over-insulation and triple glazing then I would definitely recommend a heat pump over an oil boiler every day of the week. You could also look at hybrid systems utilising both heat pump and traditional boiler, though cost may be a factor.
Thanks for all the comments and the suggestion of the Home Energy Scotland loan. I'll look into it.
I suppose I have a fear that I'll build a new house (family forever home) and then be annoyed with the heating system. I like to take hot baths, the kids have a bath every night - will i need to run an electric immersion heater to get the water hot enough for this? Seems like I will.
I know that an oil boiler can cheaply and reliably meet my heating and hot water needs but I'm unsure that an ASHP will be able to. It might be able to... but 'might' is not good enough when i'm thinking about a house that I'll probably live in for the next 20 years.
Maybe I'm looking at this the wrong way, I know there are environmental benefits with the ASHP but I don't really care about that. If anyone can point me in the direction of good case studies I'd appreciate it. I'd love to see some real data about the running costs for an ASHP in a new-build 250 m2 house.
I suppose I have a fear that I'll build a new house (family forever home) and then be annoyed with the heating system. I like to take hot baths, the kids have a bath every night - will i need to run an electric immersion heater to get the water hot enough for this? Seems like I will.
I know that an oil boiler can cheaply and reliably meet my heating and hot water needs but I'm unsure that an ASHP will be able to. It might be able to... but 'might' is not good enough when i'm thinking about a house that I'll probably live in for the next 20 years.
Maybe I'm looking at this the wrong way, I know there are environmental benefits with the ASHP but I don't really care about that. If anyone can point me in the direction of good case studies I'd appreciate it. I'd love to see some real data about the running costs for an ASHP in a new-build 250 m2 house.
mcbook said:
but 'might' is not good enough when i'm thinking about a house that I'll probably live in for the next 20 years.
Look at it another way, the UK government has already indicated they are expecting to remove gas central heating from new builds within the next decade.Using oil, already not used for grid scale energy generation, is a backwards step and how is that likely to be affected by future government steps towards decarbonisation?
Whilst your concerns are valid, they're nearly all born from poor retrofit experiences. A new build property can easily be optimised for heat pumps.
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