replace old oil boiler with new or go ASHP

[Lee66]

Hi all, I have looked at the oil boiler in the bungalow we are buying and from what I see (will get professional advice) it not only looks old but the tag on it showed only 15kw output so with the new extension I feel it will also be under powered. Question is do I go with a new oil boiler knowing that the government are trying to faze fossil fuels out or an ASHP?

Whilst the new Extension (approx 56 sq M) will be at least to the minimum latest insulation standards and have wet underfloor heating the existing bungalow(70 sq M) is 1960,s so little or no insulation.

The roof is being replaced so loft insulation can be topped up and new windows but with some solid floors and some suspended and no cavity insulation will it be too draughty for an ASHP?

 

[joe90]

Frankly ASHP,s are only any good in well insulated draught free properties although you could massively oversize it. Would mean bigger radiators as well and bigger DHW tank.

[ProDave]

This sounds like a golden opportunity to renovate the bungalow while doing the extension.  Start by under floor insulation (I bet it has absolutely none at the moment) and UFH in the original part, probably a closer pipe spacing for the UFH in the original part.

 

Carry on with the oil burner for now, I suspect in the next 5-10 years there are going to be serious grants to insulate and replace old fossil fuel boilers, there has to be with yesterdays CO2 reduction plans.

[Lee66]

23 hours ago, ProDave said:

This sounds like a golden opportunity to renovate the bungalow while doing the extension.  Start by under floor insulation (I bet it has absolutely none at the moment) and UFH in the original part, probably a closer pipe spacing for the UFH in the original part.

 

Carry on with the oil burner for now, I suspect in the next 5-10 years there are going to be serious grants to insulate and replace old fossil fuel boilers, there has to be with yesterdays CO2 reduction plans.

I intend lagging all the central heating pipes when we move stuff around but my partner wants radiators (cast iron or modern equivalent) in the bedrooms. I plan on fitting oversize ones now with room states so even if i stick with oil, which i was leaning towards in future we are ready to go ASHP and not have to spend silly amounts again on radiators. As bedrooms and Old lounge are suspended wooden floors is it worth some kind of insulation underneath? I have to way up the benefits against cost of lifting all the floor boards and insulation and this being done by trades as currently I am working away all week so no time to do myself

[Olf]

15kW of boiler output will be enough if your heat demand is lower than that - and with insulation work it is likely to be the case.

Also in well insulated building the full output of the radiators (as specified at supply temperature at 70°) will not be necessary, so even if ran straight from ASHP at ~40-50° they will do what they're intended to - keep the required room temperature. Actually the result should be better, as with lower output the temperature changes are slower than in full steam ahead - full stop mode.