Air Source Heat Pump

Author
Discussion

The Moose

Original Poster:

22,821 posts

208 months

Thursday 8th October 2015
quotequote all
Is anyone here using an air source heat pump as their sole means of heating and/or cooling?

fredt

847 posts

146 months

Thursday 8th October 2015
quotequote all
My dad is just swapping his ground source heatpump (installed 30 years ago) for a air source. house is 200m2+. Radiators and underfloor heating. About 10k I think it is

Sleepers

317 posts

164 months

Thursday 8th October 2015
quotequote all
Yes, for the last four years.

The Moose

Original Poster:

22,821 posts

208 months

Thursday 8th October 2015
quotequote all
Any things to look for/avoid?

Looking to heat/cool circa 400sqm.

Is it as efficient (financially) as it's made out to be?

Just looking for a viable alternative to oil

fredt

847 posts

146 months

Thursday 8th October 2015
quotequote all
The Moose said:
Any things to look for/avoid?

Looking to heat/cool circa 400sqm.

Is it as efficient (financially) as it's made out to be?

Just looking for a viable alternative to oil
Compared to direct electricity it is 4-5 times more efficient

Richie Slow

7,499 posts

163 months

Thursday 8th October 2015
quotequote all
We've had it at work for a couple of years now. Very cheap to run but it does freeze up quite a lot when temps are near zero. This requires a ten minute [or so] period where it defrosts itself and re-starts. Can be quite annoying, but we are generally happy with it and it works as aircon in the summer too.

The Moose

Original Poster:

22,821 posts

208 months

Thursday 8th October 2015
quotequote all
Richie Slow]We've had it at work for a couple of years now. Very cheap to run but it does freeze up quite a lot when temps are near zero. This requires a ten minute [or so said:
period where it defrosts itself and re-starts. Can be quite annoying, but we are generally happy with it and it works as aircon in the summer too.
Interesting. Does it de-ice automatically?

Do you mind if I ask what make/model you have?

Edited by The Moose on Thursday 8th October 20:52

skeggysteve

5,724 posts

216 months

Thursday 8th October 2015
quotequote all
We had it installed earlier this year and are very impressed with it so far! What it will be like in really cold weather is the question waiting to be answered.

It's very cheap to run, our electric bill dropped a lot, mind you we did have storage heaters before!

The outside unit does drip a lot of water and we are having problems with the drip tray not collecting all the water.

It doesn't get as hot or warm up as quickly as gas central heating but it's not a problem in my opinion.

It is important that your house is very well insulated and the rads/whole system is over specced - I think I heard that our was over specced by 70% - whatever that means.

If they install the outside bit at ground level make sure it is not anywhere you would normally be - when working it blows out very, very cold air and you don't want to be standing next to it!

ETA Our system is made by Dakin.

Edited by skeggysteve on Thursday 8th October 19:58

Sunnyone

146 posts

112 months

Thursday 8th October 2015
quotequote all
In a well insulated houses with the correct size of radiators they are much cheaper than oil or lpg. Should be about 2/3 of the cost.

I am putting a Dimplex A class in at the moment and I had a dimplex unit on my last house.

As with most things it is important to get the right installer.

guindilias

5,245 posts

119 months

Thursday 8th October 2015
quotequote all
Also a good idea to oversize the outdoor unit - that way it has to work less hard and will freeze up less, or possibly even not at all.
A few years ago in one of the prolonged cold periods, some of our buildings were struggling to reach 16 degrees because the heat pumps were spending more time defrosting than actually working. Doubled them up, and all was well again.
Those were public buildings though, so money wasn't as much of an issue as it would be to a homeowner buying a higher powered pump.

The Moose

Original Poster:

22,821 posts

208 months

Thursday 8th October 2015
quotequote all
Thanks for all the great information so far chaps. Most useful!

We plan to have no rads at all - all wet underfloor heating which I understand is better for air source heat pumps as it runs at a lower temperature.

How is air source for hot water?

Do you chaps have any backups of some sort? I presume an immersion heater for the hot water?

caziques

2,567 posts

167 months

Friday 9th October 2015
quotequote all
I have a business in NZ that only does underfloor heating with air sourced units.

There are various technical issues to consider with specifications, such as floor thickness, controls sizing etc etc.

400sqm is a large area - so you would run into problems with requiring three phase or multiple units.

Post some basic specs and I can give you some suggestions.

Hot water is not that straightforward - with larger houses we install a dedicated unit that only heats a cylinder - around 5kW output.

The running costs can be a lot lower than oil or gas.

BTW - all outdoor units these days automatically defrost - all air sourced units freeze up below about 6 degrees.

Jo P

2 posts

101 months

Friday 9th October 2015
quotequote all
Hello - I had a Panasonic air source head pump fitted 2.5 years ago for heating and hot water for a holiday let flat that we'd converted on the first floor of our barn. The whole system, including rads, hot water cylinders and fitting, c01308-422637st £7050. However the government gives a largeish (c.£1500 from memory) green deal payment back as an incentive - see www.ofgem.gov.uk/RHI for info before you start as there's quite a few conditions to meet and follow.

We have no gas supply and nowhere convenient to fit an oil tank. An oil fired system would be cheaper to install & run, but have more maintenance needs.

The system has performed really well, but we did pay attention to having excellent insulation. The hot water is supplied via a pressurised hot water tank and the radiators are oversized. This is necessary if you use rads as the water circulates at a lower temperature to gas and oil fired systems. However, unlike them, the system is on all the time and is not timed, so the property repains at the constant temp you set (20°C in our case, no matter how cold outside).

We used an excellent Dorset company called G.R. Edwardes Ltd from Bridport (but work far and wide). Rob Edwardes is very knowledgeable about these systems and extremly helpful to deal with and I'd thouroughly recommend them. They're on 01308-422637.

You're welcome to ring me for more info if needed - 01929-459368.

Good luck - JoP

Richie Slow

7,499 posts

163 months

Friday 9th October 2015
quotequote all
The Moose said:
Interesting. Does it de-ice automatically?

Do you mind if I ask what make/model you have?

Edited by The Moose on Thursday 8th October 20:52
We have a Mitsubishi wall mounted unit ( sorry, don't know the model) that heats about 900 sq. feet of floor space.

Yes, it does de-ice automatically, but it's quite frustrating when it's minus 5 and you're freezing your nads off.

FlipFlopGriff

7,144 posts

246 months

Friday 9th October 2015
quotequote all
We pondered over air source for about 3 years (various manufacturers through an installer that had fitted a good few) and although very efficient it was the freezing up when you needed it most that put us off. Its a listed building so having a noisy unit outside was also a problem. In the end went for biomass which has been great.
Also eligible for RHI but again lots of hoopoe to jump through but worthwhile if you are methodic and prepared to put the effort in.
FFG

Richie Slow

7,499 posts

163 months

Friday 9th October 2015
quotequote all
FlipFlopGriff said:
..... for RHI but again lots of hoopoe to jump through
FFG
I love spellcheck. rofl





Edited by Richie Slow on Friday 9th October 10:24

JD

2,769 posts

227 months

Friday 9th October 2015
quotequote all
Why not Ground Source?

Harry H

3,379 posts

155 months

Friday 9th October 2015
quotequote all
Think about the neighbours as well. Ours installed one a couple of years ago and the bloody thing on start up at 5am still wakes me.

Initially we got on to the council and as they didn't have planning for it they were made to install some sort of acoustic cover which did help. To be honest it's fine now once the thing is running but at start up it still makes a racket. Probably because there's not a lot of other noise at 5am.

We used to be quiet good friends. But what with me causing him a load of grief and expense and his refusal to set the start time nearer to 6 we don't get on well at all.

mk1fan

10,507 posts

224 months

Friday 9th October 2015
quotequote all
How well insulated / sealled is your property? If its pretty inefficient then an ASHP may not be the most cost effective solution.

Jo P

2 posts

101 months

Friday 9th October 2015
quotequote all
Hello - I had a Panasonic air source head pump fitted 2.5 years ago for heating and hot water for a holiday let flat that we'd converted on the first floor of our barn. The whole system, including rads, hot water cylinders and fitting, c01308-422637st £7050. However the government gives a largeish (c.£1500 from memory) green deal payment back as an incentive - see www.ofgem.gov.uk/RHI for info before you start as there's quite a few conditions to meet and follow.

We have no gas supply and nowhere convenient to fit an oil tank. An oil fired system would be cheaper to install & run, but have more maintenance needs.

The system has performed really well, but we did pay attention to having excellent insulation. The hot water is supplied via a pressurised hot water tank and the radiators are oversized. This is necessary if you use rads as the water circulates at a lower temperature to gas and oil fired systems. However, unlike them, the system is on all the time and is not timed, so the property repains at the constant temp you set (20°C in our case, no matter how cold outside).

We used an excellent Dorset company called G.R. Edwardes Ltd from Bridport (but work far and wide). Rob Edwardes is very knowledgeable about these systems and extremly helpful to deal with and I'd thouroughly recommend them. They're on 01308-422637.

You're welcome to ring me for more info if needed - 01929-459368.

Good luck - JoP