Air source heat pumps

[harrycatcat1]

Air source heat pumps 

Are these the things of the future? Are they any good and have many folks got them?

They reckon that they last three times longer than a combi boiler so if thats true they can't be bad, can they?

The reason I ask is my current gas boiler is 30+ years old and I am thinking that its not going to last forever.

[Jaymo]

Will let you know, in the process of installing a complete system including UFH

[figgy]

I looked at them five years ago, at that time I'd have neede two. The cost 22k that's a lot of boilers. The talking at the time was they were not reliable long term.

Things move on and if you can power them via solar panels very cheap to run. Hopefully new ones can last year's and years.

[moondoggy]

From what I have read, they are only effective in well sealed, very well insulated houses. Thus, they are no good in old, draughty properties.

I believe they run at much lower temperatures than conventional heating systems and work by being run over much longer periods and utilising the much larger heating area of under floor systems.

We have been doing this kind of research as we are looking at moving from our old cottage to a brand new house and four of the five houses we have so far considered, have air source heat pumps.

Of the other two, one was oil fired and the other LPG.

[Mark360]

I have an air source heat pump, and I would not go back to a boiler for any money,  much cheaper to run and you get a grant back from the government for 7 years, at around £300 per quarter so pays for itself and some over the time of ownership.

[Yellow Bear]

Very much depends where you live as to  air source, both for efficiency and corrosion. (had some on the Manchester/Salford border where the fins rotted off in 4 years).  Ground source are more efficient but much more expensive to install.

I suspect in "sunny Chesterfield" with it's propensity for lower temperatures they would be considerably less cost effective than south coast areas.  Also during periods of higher humidity they have a habit of "icing up" which makes them considerably less effective.

[old man]

The only time I have experienced one here was in a holiday place, the noise being pretty much continuous day and night means although a brilliant location there won't be a return.

[Old Boggy]

As has been said, they run at lower temperatures and so are more condusive to underfloor heating operating at no higher than 30 Deg C. Obviously if on a radiator system, the rads would have to be sized (larger) for the lower operating temperature.

If outside space is available then a ground source heat pump would be the better option, although initially more expensive to install.

As Figgy said, if combined with solar panels, can be pretty efficient.

Not sure if the grant system still applies as it once did on the installation of solar panels.

OB

[harrycatcat1]

Thanks for the replies 👍

I think in the circumstances that I will keep "nursing" my old boiler as long as I can.

Edited November 17, 2019 by harrycatcat1
Spelling

[millrace]

Most dont heat water to high temp so immersion are needed which usually come on automatic to keep water to temp,,this is domestic water for washing etc,,, run underfloor cause that's a lower temp,,if going thru rads alu are best but at at least cpl hundred pounds more than standard steel per rad so more cost over sizing steel not always practical as has been said you need to go full green solar etc to power them and ideally super insulated house to modern standard......oh and be about 20yrs of age to actually live long enough to see the total cost of a eco house returned.....

[figgy]

You can get split systems where the heat water too.

Best way is two separate heat pumps as they use different refrigerants. The hot water version can achieve 55deg c in optimum conditions. 

As others have said best suited to lower temp heating systems. 

I still don't think they have gotten good enough yet to replace mains gas fired boilers. 

If your on oil or lpg it could be better for you with solar to run it.

The best is ground source heat pump at 1-4 so 1kw electricity gets you 4kw of heat.  Boring a hole deep into the earth is the most stable way of getting heat.

The pipe matrix in ground is basically solar heating. The sun warms the ground and you extract that heat. No sun for a week no heat or very little for you as you've pulled the heat out. Like using a battery that needs to be recharged. You then use electricity to heat your house.

A wood burner and immersion in the hot water tank are a good idea if you go heat pump.

Edited November 17, 2019 by figgy

[Jaymo]

Our system puts the water out at 55 degrees that then goes into the mixer for the UFH, bringing the temp down.

The Supply n Return from the pump goes through the cylinder which has a normal immersion coil in case the temp is too low.

In extreme low temps the UFH has also a ‘booster’ box that additionally heats the water.

Will see how it performs, but the supplying Company have carried out all the calcs and stand by them.

Were not on mains gas, lpg could only be by 47kg bottles which is cost/labour prohibitive as the tank siting has changed since days of old.

Oil was the final option and maybe should have gone that way but with the Government RHI, the pump will have paid for itself in seven years 

[figgy]

Jaymo it looks like your the perfect circumstances for the heat pump.