chrisgeller

Fantastic! Cheers, this exactly the kind of detail I was looking for. Looks like a great resource. Concept understood, I'll have a play with it tomorrow.

Got you, thanks. Is there any reliable way to get to the solution? I can work out the kWh needs, the kW needs on a cold day, and use the COP of a candidate heat pump to work out what kW/BTU I'll need - but that all seems a bit too simple! For example, should I leave a bit of a buffer? Is there a recommended way to calculate that?

Thanks SteamyTea - not interested in DHW for now, really only looking at heating with air/air. What would you say was the best way to measure the heat load - just looking at the gas used?

Thanks Peter! Yup, I'm on a renewable tarriff, but take your point about baseload - it's hard to be truly zero-carbon! I guess taking your COP, with the grid operating at 160gCO2/kWh right now, so with a COP of 3 that's 160g CO2 for 3kWh of effective heating. Natural gas for heating is around 185gCO2/kWh, so that's 185*3= 555g CO2 for the same amount of heating. No, it's a generally pretty warm area, the existing gas heating along with the insulation doesn't really struggle. Not too worried about it being very slightly pricier in use. I guess the way I'm thinking about it is that if it only costs about a grand, has a decent chance of actually providing the required heating, and doesn't cost too much more in use, I might as well go for it. I'm looking at models like this - are there any reliable ways to see if that will actually meet my needs? Thanks again https://www.amazon.co.uk/12000-Quick-Connector-Conditioner-Conditioning/dp/B07CRR35NW/ref=zg_bs_306928031_36?_encoding=UTF8&psc=1&refRID=C5GD23GGX2ZN546BSZ9X

1990's bungalow and well insulated. Only looking for something to be able to heat (and rarely, cool) the living and kitchen space which is about 400sq ft. Want to avoid changing radiators, underfloor heating etc, and will still have other options for heating. Looking for a cheap and cheerful way to avoid burning fossil fuels. What kind of COP should I be expecting in normal use?

Interested to hear everyone's thoughts on this. Seems that heat pumps are the great hope for getting the population off burning fossil fuels, but there isn't much take-up for some practical reasons. From what I've read, getting an air source heat pump installed along with changing all your radiators in an existing property can easily cost over £10k (which a government grant can help with). You're then left with what seems to be a fairly large, potentially noisy piece of equipment, that is slower to heat up, can't produce hot water on its own, and will probably still cost more in electricity than a gas alternative. I've heard they're anecdotally more likely to break down. I've heard that there are new refrigerants being used that can get water much hotter, but then the COP seems to fall. At least this might avoid having to change all the radiators, but obviously ongoing costs may be higher. It looks like ASHPs make some sense on new-builds where you can insulate the hell out of them from the get-go and put in underfloor heating, but that doesn't really help with the pre-existing 30,000,000 homes or so in the UK. Are we anywhere near a point where the average punter would consider getting an AHSP installed on purely cost/ease-of-use considerations? Or is it unlikely the technology can get to the point of this any time soon without vast government support?