Air source heat pump - Gas backup?

anon_ymous

ProDave said:

I have a small ASHP in a self built low energy house, very pleased with it, it works well.

But even as a fan of heat pumps, if you presently have gas, then DO NOT switch to a heat pump.  It WILL cost more to run

Why do you want to change?

Hey

So essentially I thought about putting in as much insulation as I can, add solar panels, and maybe the ASHP, largely because I hoped that it would seriously reduce the amount of bills I have to pay 

I won't get an ASHP if it means that it'll end up costing more however 

lohr500

Is the house already heated by gas and if so, how old is the gas boiler?
What are your current gas and electricity costs per kWh and daily standing charges?

If the boiler is relatively new and working OK, then I can't see how adding an ASHP will save money.
In my region, the EDF April 1st SVT is £0.0728 per kWh for gas and £0.3156 per kWh for electricity.
Say the gas boiler runs at 90% efficiency, that works out at £0.081 per kWh.
If you could achieve a COP of 3 on the ASHP, it would cost £0.3156/3 = £0.11 per kWh. That is 36% more expensive than gas.
Add to that the extra cost of installation, maintenance, split control systems, etc, etc and it looks like a non starter to me.
 
Longer term, if the gap narrows between gas and electricity prices then it might make sense.

As you have suggested already, improving the insulation is a sensible thing to do, irrespective of the heat source, and I would focus on that 1st. 

ProDave

Yes, ASHP's make perfect sense for a building like mine, very well insulated, low heating demand, no gas available in this location anyway.  But I would not change a gas boiler for an ASHP at the moment.  

But we do have a government that thinks every house one day can swap a boiler for an ASHP and everything will be good.  I am not convinced yet.

anon_ymous

lohr500 said:

Is the house already heated by gas and if so, how old is the gas boiler?
What are your current gas and electricity costs per kWh and daily standing charges?

If the boiler is relatively new and working OK, then I can't see how adding an ASHP will save money.
In my region, the EDF April 1st SVT is £0.0728 per kWh for gas and £0.3156 per kWh for electricity.
Say the gas boiler runs at 90% efficiency, that works out at £0.081 per kWh.
If you could achieve a COP of 3 on the ASHP, it would cost £0.3156/3 = £0.11 per kWh. That is 36% more expensive than gas.
Add to that the extra cost of installation, maintenance, split control systems, etc, etc and it looks like a non starter to me.
 
Longer term, if the gap narrows between gas and electricity prices then it might make sense.

As you have suggested already, improving the insulation is a sensible thing to do, irrespective of the heat source, and I would focus on that 1st. 

Hi 

So this is a house I'm in the process of buying and not long after the house went on sale, they had to replace the boiler, so the boiler is effectively brand new

I wouldn't however know how much gas / electricity costs. The current owner says that they pay £100/month for both electricity and gas which doesn't necessarily reflect the cost per KwH I guess though the house is pretty well insulated

With that in mind, I guess I should perhaps wait a few years to *maybe* get an ASHP? 

markin

The uk and Europe are betting big on green Gas, So its odd the current message in the press seems to be that every home needs a heat pump, its simply not true.