Air source heat pump questions? make sense now that gas is 7p per KW?

[House man]

Got space for tank in garage, is it complex to connect up the pump to the existing house?

 

200sqm home and 3 bathrooms, what kw and which brand pump you recommend?

 

And more importantly to anyone that does have one, are you even saving? considering im looking at maybe 10k

[JohnMo]

Need a little more information.

 

Have you done heat loss calculations, these need to be completed first.  If you have them there is a spreadsheet for calculating them in boffins corner.

 

Are you doing a self install or via a grant through a registered installer?

[Redbeard]

My gas will be 10.87p/kWh on 1st July, and elec 40.7p/kWh, so I'd be looking for a CoP of 3.74 to break even. As I understand it that not an easy task on a 'slot straight in' replacement. Nothing really complex, but if you are looking to optimise CoP by keeping flow temp really low then you may (may not - it depends) have to replace some rads with larger ones (do you have enough wall?, is the Q in some rooms). 40-45  deg C is perhaps good territory for efficient running. Try turning your gas boiler temp down to 40 once the heating season is on us and see if it 'cuts the mustard'.

[ProDave]

6 hours ago, Redbeard said:

My gas will be 10.87p/kWh on 1st July, and elec 40.7p/kWh

That is more like October figures after the next rise in the energy price cap?  July SVR should be about 29p for electricity (not sure about gas)

[JohnMo]

We are 7.33p incl vat for gas per kWh.  The fixed price deals around now are circa that price (10.87p).

[ReedRichards]

An ASHP is NOT a drop-in replacement for a gas (or oil) boiler.  Because their output temperature is (typically) 50 C or less you will probably need to replace most of your radiators, possibly add a few and replace your hot water cylinder (if you already have one).    

[Mr Punter]

If your existing gas boiler is OK it will cost you more to replace it. There will be little or no saving in running costs.

[Gone West]

It doesn't even make sense for me to change from oil to ASHP in order to save money. Oil is 10kWh/litre and £1 a litre roughly, so 1kWh costs 10p.

[SteamyTea]

20 minutes ago, Gone West said:

It doesn't even make sense for me to change from oil to ASHP in order to save money. Oil is 10kWh/litre and £1 a litre roughly, so 1kWh costs 10p.

Only 19p/kWh at a gas station.

At 10p)kWh it is worth getting a CHP unit and some batteries.

20 kW is about 27 hp, so a small car diesel engine hooked up to a generator, with the coolant pumped around the house would supply that easily at part load (where it is most economic to run).

May have to bury it in a bunker to suppress noise and have the air intake and exhaust pointing away from any houses, but should not be too noisy.

[Redbeard]

2 hours ago, ProDave said:

That is more like October figures after the next rise in the energy price cap?  July SVR should be about 29p for electricity (not sure about gas)

This is Good Energy, so outwith the cap, AIUI. Our current rate is 32.15 per kWh and has been for a while. It made us think of changing, so I (idly) looked at Octopus and found v similar rates.

[ReedRichards]

6 hours ago, Gone West said:

It doesn't even make sense for me to change from oil to ASHP in order to save money. Oil is 10kWh/litre and £1 a litre roughly, so 1kWh costs 10p.

 

Only if your boiler is 100% efficient.  It would be nearer 12.5p per kWh if the boiler were 80% efficient, perhaps a more realistic value.  In which case if your ASHP could achieve an SCOP of 3 then electricity would need to cost 37.5 p per kWh to match the cost of oil.  

[Gone West]

8 hours ago, ReedRichards said:

It would be nearer 12.5p per kWh if the boiler were 80% efficient, perhaps a more realistic value.

Possibly, I don't think there is any point in rushing into any change at the moment as the market is too volatile. Grant quote 90% efficiency but I know what you're saying.

[JohnMo]

On pure financial terms bonkers, most the heating plumping needs to be changed, new cylinder and radiators, possibly the electrical supply to 3 phase.

 

Ecological terms makes some sense, but only if improve overall efficiency of house to displace the other wise needless replacement of lots of copper etc.

[ProDave]

15 hours ago, Redbeard said:

This is Good Energy, so outwith the cap, AIUI. Our current rate is 32.15 per kWh and has been for a while. It made us think of changing, so I (idly) looked at Octopus and found v similar rates.

Are you only looking at fixed price deals?  All suppliers should offer the capped standard variable rate but none really want to as they will be losing money, so you might have to insist your present supplier lets you drop onto the SVR.  Not many suppliers are taking on new customers, but if you do fond a good deal with Octopus, PM me for a referal code that will get you £50 credit.

[Redbeard]

10 hours ago, ProDave said:

Are you only looking at fixed price deals?  All suppliers should offer the capped standard variable rate but none really want to as they will be losing money, so you might have to insist your present supplier lets you drop onto the SVR.  Not many suppliers are taking on new customers, but if you do fond a good deal with Octopus, PM me for a referal code that will get you £50 credit.

 

Thanks @ProDave! I had not looked far. I think I just Googled 'Octopus Electricity Prices'.

 

This is what Good Energy say re the Price Cap: 

Why are Good Energy exempt from the price cap?

 

 

Good Energy was one of three suppliers granted a 'derogation', or exemption from the price cap, because we support renewables above and beyond other suppliers.