What does the forum think of heat pumps?

[Yellow Fang]

Would you get one? If so, what sort? If not, what puts you off?
What would you have it with, e.g. underfloor heating, new radiators, more insulation, solar hot water, PV panels?

 

[Eric Olthwaite]

what puts you off?

The second law of thermodynamics, aka "you can't move heat from a cooler to a hotter".
Ultimately, no amount of pipework routing trickery can avoid this.

 

[Ridgeway]

They are a standard install here, practically no houses built use anything else. Oil is now off limits here and gas is getting harder to get approval for new installs.

The only off putting part is the initial install cost although that tends to depend upon how deep you need to drill (here it's usually 100m).

 

[Yellow Fang]

The second law of thermodynamics, aka "you can't move heat from a cooler to a hotter".
Ultimately, no amount of pipework routing trickery can avoid this.

Yes you can if you add some electricity. That's the first law of thermodynamics.

 

[Yellow Fang]

They are a standard install here, practically no houses built use anything else. Oil is now off limits here and gas is getting harder to get approval for new installs.

The only off putting part is the initial install cost although that tends to depend upon how deep you need to drill (here it's usually 100m).

Does it have to be ground source?

 

[Ridgeway]

Answering the other points if i were installing a new system here it would be:

PV around 40 x 200w panels
Solar water heater
Heat pump to feed underfloor heating
Insulation overall up to "Minergie" standards (Passivhaus) i think this is called "low energy" in the UK ?

The later is only really achievable if we're talking new build, our house is old so i'll be focusing on the first 3 points over the next years.

 

[Ridgeway]

Does it have to be ground source?

Doesn't have to be and there's more and more air source but ground source is well established and accepted here. Next install for us will be ground source once the gas boiler dies.....

 

[Yellow Fang]

I sometimes wonder if ground source vs air source is a case of the excellent being the enemy of the good enough. People who are interested in it read that ground source heat pumps are better, find out it's more expensive and/or requires digging up your garden. but don't want air source because it's second best, then lose interest.

 

[roubaixtuesday]

The second law of thermodynamics, aka "you can't move heat from a cooler to a hotter".
Ultimately, no amount of pipework routing trickery can avoid this.

Refrigerators are a figment of my imagination?

shoot. I'd better go eat that cheese pronto!

 

[contadino]

I had a MHRV fitted to my previous house and it worked pretty well. We had a couple of kw of pv on the roof so the cost of running it was zero. We went from using the (gas) heating for maybe 4 months each year to a few hours on 11 days in 15 months.

I probably didn't recoup the cost because we moved house, but it'd pay for itself in 3 or 4 years.

When I've got the new house sufficiently insulated I'll be getting one fitted for sure.

ETA: not sure if you meant to include MHRVs as a heat pump but thought I'd chip in anyway

 

[annedonnelly]

I've had an air source heat pump for years. It's been no problem at all. I think the first winter after it was installed we had a long, long freeze with temps of about -10C and it worked perfectly.

I also have solar hot water and PVs. And I got new radiators when the heat pump went in.

 

[OldShep]

I’ve had a ASHP for ten years.
installed for £1400, ten years on with no problems I’m now going to give it a service. I could have had it serviced every year at a cost of £120 ( quoted 10 yr ago) to keep a 10 year warranty alive. I think my gamble has won.
plus side is it’s been very cheap to run and keep the house warm and also cool on the two hot days we get each year.
down side a homes biggest demand is when it’s coldest outside which is also when the machine is less affective. We’ve always had to supplement with a wood stove winters evenings. The constant air movement gives me a cold nose.
Experience tells me
Sizing and placement of the unit is crucial. I wish I’d put in the biggest I could before 3 phase is required. I wish I’d put the indoor unit in a different location.
After 10 years we have recently stopped using it and returned to full price electric heating. It keeps us warmer and it costs more than double to run. This experience has also taught us the calculations on heat loss for the living area have been very optimistic. Don’t underestimate how much loss there are from windows and patio doors.
I looked into buying a bigger better unit and was impressed with a guy near Aberdeen who supplies units produced for use in, I think it was Finland. Claiming real efficiency down to -30C outside. Once bitten twice shy and aged 70 I decided not to take the risk on an outlay nearly three times more than my last foray into heat pumps. If I was still aged 60 then I think I would have taken a punt with his machine.
i intend, this summer, moving our ASHP to the other end of the house to heat an area less than half of what it does now. I’m fairly confident that will be a success.

 

[Yellow Fang]

I had a MHRV fitted to my previous house and it worked pretty well. We had a couple of kw of pv on the roof so the cost of running it was zero. We went from using the (gas) heating for maybe 4 months each year to a few hours on 11 days in 15 months.

I probably didn't recoup the cost because we moved house, but it'd pay for itself in 3 or 4 years.

When I've got the new house sufficiently insulated I'll be getting one fitted for sure.

ETA: not sure if you meant to include MHRVs as a heat pump but thought I'd chip in anyway

What's an MHRV?

 

[Yellow Fang]

I’ve had a ASHP for ten years.
installed for £1400, ten years on with no problems I’m now going to give it a service. I could have had it serviced every year at a cost of £120 ( quoted 10 yr ago) to keep a 10 year warranty alive. I think my gamble has won.
plus side is it’s been very cheap to run and keep the house warm and also cool on the two hot days we get each year.
down side a homes biggest demand is when it’s coldest outside which is also when the machine is less affective. We’ve always had to supplement with a wood stove winters evenings. The constant air movement gives me a cold nose.
Experience tells me
Sizing and placement of the unit is crucial. I wish I’d put in the biggest I could before 3 phase is required. I wish I’d put the indoor unit in a different location.
After 10 years we have recently stopped using it and returned to full price electric heating. It keeps us warmer and it costs more than double to run. This experience has also taught us the calculations on heat loss for the living area have been very optimistic. Don’t underestimate how much loss there are from windows and patio doors.
I looked into buying a bigger better unit and was impressed with a guy near Aberdeen who supplies units produced for use in, I think it was Finland. Claiming real efficiency down to -30C outside. Once bitten twice shy and aged 70 I decided not to take the risk on an outlay nearly three times more than my last foray into heat pumps. If I was still aged 60 then I think I would have taken a punt with his machine.
i intend, this summer, moving our ASHP to the other end of the house to heat an area less than half of what it does now. I’m fairly confident that will be a success.

Was that an air to air heat pump, i.e. cold air from the outside, warm air to the inside (rather than radiators or underfloor heating)? What's it power rating?

 

[OldShep]

Was that an air to air heat pump, i.e. cold air from the outside, warm air to the inside (rather than radiators or underfloor heating)? What's it power rating?

Yes that is A2A experience.
The installer I used back then felt the expense of underfloor wasn’t worthy of the premium of UFH. Whether he was right or afraid of the unknown I can’t say.
whilst I have 2/3 of an acre he also felt my ground is severely shaded with trees any suitable ground would just get colder and colder and once again not worthy of the initial cost.