Heat pump install vs Gas

brewerdave

Mstty said:

lohr500 said:

Hi matelodave, as someone who has an ASHP, what efficiency factor are you seeing in the real world?

Hi Mstty, with your ASHP setup are you seeing an efficiency factor of 4 on an annual basis? I did some research and lots of googling last year when we were considering an ASHP and most people seemed to think a factor of 3 was bordering on the optimistic side of reality, especially in winter when the heating is needed most.

I'm really interested to know how ASHP installations are performing in the real world.
There seem to be lots of posts from people who are unhappy with the consumption of their ASHP setups and also lots of debate and confusion on the optimal settings for the control systems. 

I don't think retro fit systems would be able to match what we are seeing but my opinion is every new house should have an ASHP installed, ideally with solar panels and solar hot water heating. That truly would be the trifecta of energy saving and cheap running of a house.

I agree wholeheartedly with you on this BUT as I have mentioned in other threads, the housebuilders will not do this until/unless compelled by watertight planning legislation. About 18 months ago, I asked an agent on a current development of 600+ houses near our village WHY no solar or ASHPs - his answer ? - because the buyers won't pay the premium (true reason ,I suspect ,because they get gas boilers and radiators for peanuts !! and ASHPs etc would hit their profits)

Reed_Richards

markin said:

Reed_Richards said:

Alnat1 said:

What sort of property do you have? An ASHP works more economically in a really well insulated (probably more modern) building.

This is often stated and it's true but equally it's tosh.  Any boiler or other heat source works more economically in a really well-insulated building.  There is nothing different about an ASHP in this regard; it's just the same as everything else.    

The must come a point where a low flow temp can't keep up with the heat loss or water usage and the AUX heater is burning away 24/7 in cold weeks trashing the advantage over Gas. Or do we always just put that down to Bad design at install, Or the homeowner that can't work out how to run it efficiently, Or the 3 different service men that can't fix it and simply say 'Its Fine' until the owner or council rip it out and install gas.

 

The advantage over gas works out on an average taken over the entire year.  Heat pumps are rated with an SCOP, Seasonal Coefficient of Performance.  This depends on your choice of operating conditions, for my heat pump the rated SCOP is 3.2 for a water flow temperature of 50 C so that means on a yearly average I get 3.2 kW of heating for every 1 kW of electricity used.  This means if the cost of electricity per kW is less than 3.2 times the cost of gas per kW then there should be a running cost advantage for my heat pump over a gas boiler.

I don't have underfloor heating, just radiators.  I have never needed to run my heat pump 24/7 and my house has always been warm enough over the last two winters.  This means it never got so cold outside that my heat pump needed to invoke the auxiliary heater.  That just as well because it doesn't actually have one, not all heat pumps do.