funduffer wrote:A few points:
1. If you are considering a heat pump you need a proper heat loss survey of your house to accurately determine the size needed. You can have a go at this yourself with the heatpunk tool: https://heatpunk.co.uk/home. In this you can adjust radiator sizes/types and flow temperature to see what difference it makes. But you probably should get one done by an expert.
2. On most heat pumps you can adjust the flow temperature - the higher the temperature the lower the efficiency (COP). Some heat pumps can operate at the flow temperature of a gas boiler, but with low COP. So there is a trade-off between spending money to increase radiator size and improve insulation versus heat pump efficiency (and hence electricity usage). The optimum will depend on your particular property and what exists in it at the start.
3. I have had a heat pump quote for a 3 bed bungalow from Octopus, including hot water tank and some new radiators of £6230, net of the £7500 grant available in England.
Home energy Scotland produced a comprehensive report detailing most (if not all) of what you say. The conclusions were pretty similar to that of the Scottish Power surveyor.
My house is a 3 bed semi detatched. I would be £3149 after the grant....but as I said before, if I factor in having to replace the aging storage heaters with modern ones and replacing the immersion HW tank anyway....I'm actually £470 up.......