Air Source Heat Pump or Oil Boiler

[calson]

I'm about to build a 180m timber frame house later this year and as the only onsite power supply is electricity i'm considering a heat pump with underfloor heating. Using economy 7 or 10 to run the pump and heat the hot water with a couple of storage heaters upstairs, maybe.

I've also noticed that trying to get good solid info on them isn't easy, similar to underfloor heating 12 years ago which is now commonplace.

Does anyone have a air source pump and what do you think of it?

Cheers, Calum

 

[BigBurner]

ASHPs are only suitable for homes that have a high insulation value. Ensure your house has Warmcell insulation sprayed into the voids and is air-tight. That is essential.

ASHP's can underperform in winter and are only suitable for low temperature UFH. Have any air extraction of the house run across the heat pump to claw back some wasted heat. You will have resistance heaters supplement the DHW in winter too.

Best consider a ground source heat pump, which perform much better. But, these have a very high capital cost, and in reality it would be better to spend the money on insulation, air-tightness and triple glazed windows. Once the house gets to a point of heat loss, a full heating system is not needed and basic, cheap to install, service free, electric resistance heaters are then feasible. They are rarely on so economical to run. A boiler is around £100 per ann. to service. That £100 pays for a lot of electricity to heat the house and DHW.

So, insulate like hell, make it air-tight, then do the heat loss calculations. You may find just cheap, service free electric heaters is all you will need.

 

[calson]

Many thanks for your reply Bigburner and confirming my suspicions regarding the ASHP's limitations.
I live in the Western Isles and the house will be a kit coming from a mainland manufacturer with 6" studwork conforming to the present regs etc. The importance of airtightness like you say would be imperative here as it can get quite draughty in the Winter.
Any suggestions for a good oil boiler?

 

[BigBurner]

Many thanks for your reply Bigburner and confirming my suspicions regarding the ASHP's limitations.
I live in the Western Isles and the house will be a kit coming from a mainland manufacturer with 6" studwork conforming to the present regs etc. The importance of airtightness like you say would be imperative here as it can get quite draughty in the Winter.
Any suggestions for a good oil boiler?

Make sure you have Warrmcell sprayed in cellulose insulation in the 6" studs. This also makes the frame air-tight too, so kills two birds with one stone. Warmcell performance the same as insulation that is 25% thicker, so more again.

Oil boilers? Whatever the local dealers supply and fix. That is the most important point where you live.

 

[Agile]

Heat pumps only become worthwhile from an economic or green perspective when there is plenty of cheap hydro power.

Thats not something we have much of here !

You suddenly reminded me of a dreadful character a long time ago who seemed to think that he owned the NOSHEB !


Tony

 

[calson]

Thanks also for your reply Agile, maybe not the NOSHEB but you do realise that it's our oil, or at least what's left of it.

It seems that the blown Warmcel 500 into wall cavities can only be done by an approved installer. The nearest installer to me is about 300 miles away and wonder if it can be done on a DIY basis.

 

[Agile]

They do need a special air pump to blow the insulation into the cavity.

I dotn see whats the special advantage of that stuff over the normal sheets.

The NOSHEB guy was a Mr Fulton!

Tony

 

[BigBurner]

Heat pumps only become worthwhile from an economic or green perspective when there is plenty of cheap hydro power.

Thats not something we have much of here !

Economic has nothing to do with hydro power. Heat pumps are worthwhile but you need to do the home work and have them installed properly to a suitable system.

 

[BigBurner]

They do need a special air pump to blow the insulation into the cavity.

I dotn see whats the special advantage of that stuff over the normal sheets.

That is because you know nothing of construction and insulation.

 

[BigBurner]

Thanks also for your reply Agile, maybe not the NOSHEB but you do realise that it's our oil, or at least what's left of it.

It seems that the blown Warmcel 500 into wall cavities can only be done by an approved installer. The nearest installer to me is about 300 miles away and wonder if it can be done on a DIY basis.

They sell packs of it you mix yourself and trowel in.