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Replacing Storage Heaters with a Heat Pump in a Stone Cottage

Paul1098 · 2026-09-27T20:22:39Z

Hi Mars,Just at the start of my Renewable journey and watched a couple of your Youtube videos on Heat pumps and Installers.I'm not surprised that people struggle to find a decent installer for heat pumps as we have struggled to get a decent installer for a new oil boiler in the recent past and some have even struggled to service it.Looking to use the BUS to replace old storage heaters with a heat pump in an stone cottage - another complication being it's in a national park with Article 4 restrictions but hopefully rear back yard is OK.I'm OK with heat loss calcs and pipe sizing for normal high temp heating systems but can imagine the low temps involved with heat pumps cause a few extra problems.

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Air Source Heat Pumps (ASHPs)

Last Post by cathodeRay 25 minutes ago

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Toodles

(@toodles)

Famed Member Contributor

Joined: 4 years ago

Posts: 2996

09/10/2026 6:51 pm

@jamespa “The answer is …….. 42.😉

Toodles, heats his home with cold draughts and cooks food with magnets.

👍

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EtchedPixels

(@etchedpixels)

Estimable Member Member

Joined: 5 months ago

Posts: 158

09/10/2026 7:06 pm

Posted by: @paul1098

↑

@cathoderay https://www.stelrad.com/starsapp/login - you have to setup an account and I can't remember how onerous it is as it was 10 years ago when I started using it.

MCS and British standards do have air change values that generally seem to be 0.5 (I assume that's room volumes but not fully checked that yet) they also include for chimneys and extractors so comprehensive.

Just had my first quote of over £18k so if that's the general cost of an ASHP + central heating install for a small 2 bed cottage then my journey will be stopping and i'll go for LPG.

We got quoted 33 grand for our victorian solid stone pile by a heatgeek engineer who to be fair told us not to bother, so I bought and installed some air/air kit and did it that way instead. No grant at the time (and still no worthwhile one now) but cost me slightly over 1/10th of the cost of air/water in this big solid stone building. Kept the gas as backup although all has actually done is heated some water.

What comes out affordable can depend heavily upon the building and what is already present. For us the existing plumbing was mostly inadequate, some of it inaccessible and the building has a high heat loss so would have involved a lot big big radiators to make it work.

With air/air we just heat the rooms where the fires were traditionally and leave some doors open. It then works the way the victorian designers intended.

👍

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cathodeRay

(@cathoderay)

Famed Member Moderator

Joined: 5 years ago

Posts: 3084

09/10/2026 7:19 pm

Posted by: @jamespa

↑

I will post the full explanation later if nobody else does and anyone is interested (both of which seem unlikely)

I'm certainly interested in it. I tried to work out how the units in the formula got to what is a single count of watts, but failed. The formula is delta t (in °C) x a constant x a volume (in cubic metres) x the ACH which despite being a single count is in "m^3/hr per m^2 of [e]xternal area" which I think resolves to m^2/m meaning we have °C x m^3 x m^2/m...at which point my brain gives up!

Midea 14kW (for now...) ASHP heating both building and DHW

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