UPDATED: Air Source Heat Pumps/Air Con - Full Info & Guide, is it cheaper to run than mains gas?

TiredGeek

vince31 wrote: »

Disagree with going for mains gas!

I live in a 4 bed detached house (built 2000) on a standard estate in UK. Last year my mains gas bill for heating and water etc came to £645. The projected cost of heating and hot water provided by an Air Source Heat Pump (8Kw) is £465. Thats a saving of £180 pa. Factor in an RHI payment of £521 pa for the next 7 yrs on top of the savings and thats a substantial amount (£700) net gain. On top of that, my PV panels will be feeding in free electric (rather than exporting it for nothing) when the sun is out so its even cheaper to run.

The installer GUARANTEES lower running costs and will refund the difference if these figures are not borne out in real world operation!

Correct me if I'm wrong, but doesn't the RHI specifically exclude any property with access to mains gas?
If I had mains gas there is no way I'd use ASHP, it's far more complex than a gas boiler to get right. It might be cheaper to run but it definitely costs a lot more up front.

CALVI

TiredGeek wrote: »

Correct me if I'm wrong, but doesn't the RHI specifically exclude any property with access to mains gas?

The RHI is targeted at off-gas households, and the tariffs are calibrated to create attractive rates of return for this group, but it is not limited to off-gas houses. On gas houses can be perfectly eligible to receive RHI payments.

aggydebt

Hello,

I see posts here kind of stopped but hopefully someone can help me...
We live in a 4 bed detached, with some insulation like partial roof and some walls. Whole house has concrete floor that we believe are not insulated (done in around 85). Had very old oil boiler which we thought was expensive. Replaced to radiant heat panel which now cost a fortune to run and impossible to raise room temp to say 23C when outside is -1 or similar. Getting cold spots where condensation comes onto wall in small patches (only upstairs as whole of first floor is under roof timber structure uninsulated stud walls).

Total area is about 200sqm. 2 bathrooms.

I am considering installing underfloor heating into kitchen and hallway (42sqm) as part of the renovation project (the rest of the house is done).
And air to air blower units in few other cold rooms downstairs.

Can anyone advice whether these two different types can be run by single heat pump? Is it really worth the investment. And most importantly- can they deliver 23C shouls I wish so! Or should I go back to oil or LPG.

I want house to be on average 20-22C at cold temperatures.

I no longer have radiators so those would need installation.

richardc1983

aggydebt wrote: »

Hello,

I see posts here kind of stopped but hopefully someone can help me...
We live in a 4 bed detached, with some insulation like partial roof and some walls. Whole house has concrete floor that we believe are not insulated (done in around 85). Had very old oil boiler which we thought was expensive. Replaced to radiant heat panel which now cost a fortune to run and impossible to raise room temp to say 23C when outside is -1 or similar. Getting cold spots where condensation comes onto wall in small patches (only upstairs as whole of first floor is under roof timber structure uninsulated stud walls).

Total area is about 200sqm. 2 bathrooms.

I am considering installing underfloor heating into kitchen and hallway (42sqm) as part of the renovation project (the rest of the house is done).
And air to air blower units in few other cold rooms downstairs.

Can anyone advice whether these two different types can be run by single heat pump? Is it really worth the investment. And most importantly- can they deliver 23C shouls I wish so! Or should I go back to oil or LPG.

I want house to be on average 20-22C at cold temperatures.

I no longer have radiators so those would need installation.

My advice would be that unless you have mains gas then heat pumps are the way forward. If mains gas is an option then go for this as still cheaper per unit than electricity is.

In summary yes the system will work well with a mix of under floor heating (very even temperatures) in fact 22C with underfloor heating would feel quite sweltering as the temperature is spread so evenly you dont get cold or hot spots as the air is heated from the ground up. The air to air fan coil units are also excellent and plus you have the benefit of cooling in the summer.

My advice on the type of air to air blower units would be the floor mounted console units that blow heat out at floor level rather than high wall units as these struggle sometimes to get the air down to the floor level due to heat rising. They are a little more in cost outlay but not by much. The benefit of air to air is that you also have cooling in the summer and some systems make use of the rejected heat removed from your rooms indoors and use this to heat the hot water.

So yes, it will work and very well but you have to have a good install. Underfloor heating and fan coil units make great use of the lower water flow temperatures a heat pump supplies so this means the overall efficiency is good.

aggydebt

Thanks very much for your advice. We have no gas available otherwise it would be straightforward decision.

Regarding floor mounted units- the problem would be to hide the cable pipe work. Would have to be chased into walls Top units easier to install. Is it worth the hasle and extra expense of installation to get floor mounted..?

Also, another thing I am thinking is that if I sort out cold issue downstairs and keep it always warm, my upstairs rooms would be reasonably warm and I will keep radiant heat panels to top it up. Or am I wrong in thinking I can rely on downstairs warmth. Its hardwood floors upstairs.

richardc1983

aggydebt wrote: »

Thanks very much for your advice. We have no gas available otherwise it would be straightforward decision.

Regarding floor mounted units- the problem would be to hide the cable pipe work. Would have to be chased into walls Top units easier to install. Is it worth the hasle and extra expense of installation to get floor mounted..?

Also, another thing I am thinking is that if I sort out cold issue downstairs and keep it always warm, my upstairs rooms would be reasonably warm and I will keep radiant heat panels to top it up. Or am I wrong in thinking I can rely on downstairs warmth. Its hardwood floors upstairs.

Console (floor) units pipe and wire in the same as high wall mounted units. The only difference is they are fixed to the wall at a lower level rather than a higher level. The pipework cables still goes out through the wall. The install costs and procedure are the same the initial unit out lay is a little more though at perhaps £100 more than a high wall mounted unit.

I would ditch the radiant panels upstairs, they use too much electricity. Do this properly, go for floor mounted units or even better underfloor heating or even radiators connected to the same system. Upstairs this would work well.

Re the condensation, have you also considered installing a heat recovery ventilation system to bring fresh air in and exchange stale air?

Cardew

aggydebt wrote: »

Thanks very much for your advice. We have no gas available otherwise it would be straightforward decision.

.

Oil central heating at approx. 2.5p/kWh is currently cheaper than gas - although it may not stay low in the long term

richardc1983

Cardew wrote: »

Oil central heating at approx. 2.5p/kWh is currently cheaper than gas - although it may not stay low in the long term

I wish the price of leccy would come down in this country!!

aggydebt

Oh im sooo confused now! Spoke to a very experienced heating engineer that dealt a lot with oil and lpg, and when I mentioned heat pump he just said 'i swear my life, you wont be happy, don't do it'.
He said in Scotland they had a lot of these taken out. Of course, you might say it's all due to bad cals/installation, but I don't want to be a hit and miss example myself, especially after the 'new technology' of radiant heat we went through at a great great loss!

He said to go with LPG. Cheaper than any installation costs and guaranteed hot water and warmth. I want my house to be 20-23 at al times. Don't want luke warm rads or giessing if I'll have enough hot water for everyone to bath. Probably will cost 1.5kna year but thats half what we are paying now.

At least from your advice I understand that I should go for full house wet system rather than mixing water and air.

Cardew

aggydebt wrote: »

Oh im sooo confused now! Spoke to a very experienced heating engineer that dealt a lot with oil and lpg, and when I mentioned heat pump he just said 'i swear my life, you wont be happy, don't do it'.
He said in Scotland they had a lot of these taken out. Of course, you might say it's all due to bad cals/installation, but I don't want to be a hit and miss example myself, especially after the 'new technology' of radiant heat we went through at a great great loss!

He said to go with LPG. Cheaper than any installation costs and guaranteed hot water and warmth. I want my house to be 20-23 at al times. Don't want luke warm rads or giessing if I'll have enough hot water for everyone to bath. Probably will cost 1.5kna year but thats half what we are paying now.

At least from your advice I understand that I should go for full house wet system rather than mixing water and air.

I tend to agree with your very experienced heating engineer! - except I can't see why he would advocate LPG over oil. That said, there are respected posters on this forum who are happy with their system and also others very unhappy!


Have you read this thread?


http://forums.moneysavingexpert.com/showthread.php?t=2968958&highlight=should+do+better


In particular read the two x 12 month trials carried out by the Energy Saving Trust.