Should I or Shouldn't I ASHP?

[Nickfromwales]

Anybody want to have a stab at how long an ASHP will last, vs a good quality gas boiler?

 

This also needs to be factored in. 

[JohnMo]

About the same. ASHP shouldn't last as long as good fridge. But technically a heat pump produced today will be over taken efficiency wise every few years.

 

A poor boiler or heat pump install, is unlikely to last a a good one. So many variables.

Edited 15 hours ago by JohnMo

[Beelbeebub]

If you aren't bothered about claiming the grant then you could install a muktisplit A2A heatpump

 

This would give you cooling in the summer and leave the gas boiler for water and backup heating in winter. (summer water could be immersion heater from PV?) 

 

You haven't mentioned if you have a gas hob - factor that cost in if you want to get rid of gas altogether. 

[Oz07]

1 hour ago, JohnMo said:

About the same. ASHP shouldn't last as long as good fridge. But technically a heat pump produced today will be over taken efficiency wise every few years.

 

A poor boiler or heat pump install, is unlikely to last a a good one. So many variables.

Are heat pump warranties 10 years or more like a boiler? Genuine question I've never looked in to them

[Michael_S]

Suppose the heat pump gets a cop of 4 (not impossible given the low flow temps you are already operating at)

 

14.3k gas usage at 5.5p per kwh costs £786pa

14.3kwh gas input at 95% efficacy gas boiler divided by a cop of 4 at 7p per unit off peak rate using battery timeshift costs £238pa

 

In theory your heat pump install should be cheap, only need a small unit (6kw?) and only change to plumbing might be to replace the hot water tank with a large coil one and hopefully your battery would be big enough to timeshift your total demand even on the coldest days?  Risk is that the new govt plan to prioritise batteries may lead to a reduction in the potential savings from timeshifting due to increased arbitrage.

[JohnMo]

1 minute ago, Michael_S said:

Suppose the heat pump gets a cop of 4 (not impossible given the low flow temps you are already operating at)

 

14.3k gas usage at 5.5p per kwh costs £786pa

14.3kwh gas input at 95% efficacy gas boiler divided by a cop of 4 at 7p per unit off peak rate using battery timeshift costs £238pa

Plus you need to take into account the deletion of the standing charge, if the boiler is deleted which is currently £127 per year.

[Roger440]

4 hours ago, Michael_S said:

Suppose the heat pump gets a cop of 4 (not impossible given the low flow temps you are already operating at)

 

14.3k gas usage at 5.5p per kwh costs £786pa

14.3kwh gas input at 95% efficacy gas boiler divided by a cop of 4 at 7p per unit off peak rate using battery timeshift costs £238pa

 

In theory your heat pump install should be cheap, only need a small unit (6kw?) and only change to plumbing might be to replace the hot water tank with a large coil one and hopefully your battery would be big enough to timeshift your total demand even on the coldest days?  Risk is that the new govt plan to prioritise batteries may lead to a reduction in the potential savings from timeshifting due to increased arbitrage.

 

Where are the battery costs in your numbers?

 

[Michael_S]

3 hours ago, Roger440 said:

 

Where are the battery costs in your numbers?

 

OP said they already had 30kwh battery.  There is a cycle life and therefore a cost per cycle and of course cycle efficiency to update my first order approximation.....