mikechadwick
pfm Member
Anyone have one of these or thinking about getting one? With the Boiler Upgrade Scheme this could be a good time but I’m interested to know other’s experiences.
Air Source Heat Pumps
- Thread starter mikechadwick
- Start date
Everyone else is thinking the same. From retro fit exterior wall insulation, ashp/gshp to PVs. My partner is an academic and practicing architect specialising in this sort of thing. They have seen enquiries explode through the roof since the fuel bills thing. Competent contractors (emphasis on the competent) can't keep up and are refusing to price work years ahead even without the uncertainty of materials price increases. Manufacturers, especially of pvs apparently, can't keep up either. Don't rely on many of the claims currently being made for ashp and especially gshp and don't even consider the former in a dwelling that is not already or about to be fitted out to near passivhaus standard. This is a sector just crying out to be exploited by crooks given the disaster of the failed govt grant scheme.
Shift across to the EU for a moment where said partner's sister is having all this sort of thing done Inc ashp and work is moving along nicely with a 110% grant from the state (the 10% deals with the beaurocracy and legalities). It's a different world.
Shift across to the EU for a moment where said partner's sister is having all this sort of thing done Inc ashp and work is moving along nicely with a 110% grant from the state (the 10% deals with the beaurocracy and legalities). It's a different world.
mikechadwick
pfm Member
Thanks
Half the replies you will get will tell you they don’t work, but that’s bollocks… they just need to be installed and sized properly and put in in the right environment. If you have a well insulated property they work extremely well but if you live in an older property that is difficult to insulate you could struggle. Radiators need to be much larger than those for conventional systems, but underfloor heating is the best solution. PM me if you want chapter and verse.
I actually think that ASHP ought to work very well in the UK. After all it never gets especially cold or hot in the UK. A cold night in the UK might be -5C so your delta is only 25 deg C. 30 deg C tops. Compare and contrast say Canada or Russia where it can routinely be -30C, delta T 50 deg C, you have to work bloody hard to find the heat energy in that.
Richard Lines
pfm Member
Good Afternoon All,
14yrs experience with Solar PV installed, 5 1/2yrs with a GSHP and Solar hot water, 2yrs with a PW2 and this in an 1859 stone farmhouse and 4yrs with an EV - been there, done that and most certainly dealt with contractors who, frankly, haven't always had a clue.
I can see nothing in the the current government schemes to change this.
I don't profess to be an 'expert' but am always willing to offer advice.
The mantra remains - insulate, insulate and, as a back-up, insulate!
Regards
Richard
14yrs experience with Solar PV installed, 5 1/2yrs with a GSHP and Solar hot water, 2yrs with a PW2 and this in an 1859 stone farmhouse and 4yrs with an EV - been there, done that and most certainly dealt with contractors who, frankly, haven't always had a clue.
I can see nothing in the the current government schemes to change this.
I don't profess to be an 'expert' but am always willing to offer advice.
The mantra remains - insulate, insulate and, as a back-up, insulate!
Regards
Richard
5 x ASHP here at work.
Excellent and do as intended.
Some very big caveats.
Place needs to be **completely** draught free (and I mean totally).
Place needs to be very, very well insulated. Everywhere.
Preferably mechanical ventilation with heat recovery installed first, as no air can enter from draughts any more.
This is highly unlikely to be a fact in most of the UK housing stock.
To achieve the levels I talk about is a colossal job and very expensive.
Glad I did it, and will certainly be worth doing for me now with the cost of electric.
Simply do not expect them to work in the usual UK house though.
If the above are not met, expect huge bills and additional heating required.
Excellent and do as intended.
Some very big caveats.
Place needs to be **completely** draught free (and I mean totally).
Place needs to be very, very well insulated. Everywhere.
Preferably mechanical ventilation with heat recovery installed first, as no air can enter from draughts any more.
This is highly unlikely to be a fact in most of the UK housing stock.
To achieve the levels I talk about is a colossal job and very expensive.
Glad I did it, and will certainly be worth doing for me now with the cost of electric.
Simply do not expect them to work in the usual UK house though.
If the above are not met, expect huge bills and additional heating required.
martin clark
pinko bodger
This is an excellent point - this is still the first/ best-value thing to do regardless of heating type/ fuel source, after draught-stripping. The RoI is rapid, and long lived; and essential once you are even ony approaching decent airtightness. I've mentioned this over the last 10yrs++ here.
UK Building Regs Appd Doc Part F has just been updated (in force from 15th June) and finally recognises this, in support of the updated 2021 version of app Doc part L (conservation of energy). Part F Vol 1 deals with domestic buildings.
gingermrkettle
Deep vein trombonist
Getting one put in in a couple of weeks time. 70s detached house with recent triple glazing (u value c. 0.9), MVHR (which is a bit of a pig to retrofit) and PV. The installer who put in our sunamp reckoned we should be completely fine running at 45 degrees output given the calculated heat losses.
MVHR also can save a large amount on tumble drying...
MVHR also can save a large amount on tumble drying...
mikechadwick
pfm Member
Thanks everyone - it's really got me wondering if it's the right thing to do as, being a typical UK house, there's no way it's completely draught proof. Very interesting about MVHR which I'd never considered. More thought required 
gingermrkettle
Deep vein trombonist
Ours isn't completely sealed to Passivhaus standards by any means (although the majority of the ventilation previously was from how badly the windows were installed).
Lots of good advice in this thread and others that have been linked to.
Investing in high levels of insulation, then sealing the building and adding a mechanical heat recovery system will make the building very cheap to live in for the rest of your time living there. The other benefit of doing this is that you can buy a smaller heat pump which will deliver the required thermal energy, whereas just installing a heat pump without addressing the issues listed, will cost you more to purchase and install a bigger unit and will cost you more to run it whilst living in that house (and for any replacement units that might be required long into in the future).
If you can get the house insulated and sealed to close to passive house or to passive house standard, then an exhaust air heat pump should be viable:
https://www.nibe.eu/en-gb/products/heat-pumps/exhaust-air-heat-pumps
Then add solar panels to provide enough electrical energy to drive the heat pump and you have free thermal energy for much of the year.
Investing in high levels of insulation, then sealing the building and adding a mechanical heat recovery system will make the building very cheap to live in for the rest of your time living there. The other benefit of doing this is that you can buy a smaller heat pump which will deliver the required thermal energy, whereas just installing a heat pump without addressing the issues listed, will cost you more to purchase and install a bigger unit and will cost you more to run it whilst living in that house (and for any replacement units that might be required long into in the future).
If you can get the house insulated and sealed to close to passive house or to passive house standard, then an exhaust air heat pump should be viable:
https://www.nibe.eu/en-gb/products/heat-pumps/exhaust-air-heat-pumps
Then add solar panels to provide enough electrical energy to drive the heat pump and you have free thermal energy for much of the year.
martin clark
pinko bodger
A very general point on this though - if you don't have/ are not planning (maybe don't have space for!) MVHR - don't worry about the small incidental 'calibrated leaks' left.
You and the building fabric needs some background ventilation to purge vitiated air, the water vapour you exhale, etc. In the absence of mech vent you might even be surprised how large the required free area of the trickle vents for windows really is (8000sq.mm - about the face area of 1 -1/2 bricks, per habitable room -varies by room use)
The point is - it' best to have control over such. Definitely Not to get rid of entirely!
PsB
Citizen of Nowhere™
I am always puzzled by this notion i read here that heat pumps only work on a very well insulated house. Surely, a HP kW does the same job as a gas boiler kW. It is obvious that a house with abundant air leaks requires more kWs to maintain a given temperature. But I don't see what the heat source has to do with it.
Somafunk
pfm Member
A heat pump system has a low output that cannot compete with the heat loss experienced in a poorly insulated house and will cost a fortune to run, I have a heat pump system for heating/hot water and if switched on, especially in winter it costs a fortune to run (£15 day) so I have it permanently switched off and rely on my wood burner for heat.