Heat pumps with extra batteries

maf20

Only thing I need to workout now is who would install one. Octopus won’t as I don’t have enough ground floor wall space. 

The last time I got a quote from another company (one who would install high up on the side of the house), it was thousands and thousands more than octopus. 

Our gas boiler will need replacing at some point, but I’m trying to get ahead of that and put that would be cost towards a heat pump  

Reed_Richards

But I agree, @maf20; you could look at what you need on the worst day and get enough battery storage for that but if such days are rare maybe you should accept that on a few days each year you won't have enough battery storage.  In principle an ASHP system designed to MCS standards and performing exactly to those standards won't have enough output to keep you house warm for one day a year.  Applying a similar philosophy to battery storage could give you enough for almost all of the time for less outlay. 

FreeBear

maf20 said:

Only thing I need to workout now is who would install one. Octopus won’t as I don’t have enough ground floor wall space. 

The last time I got a quote from another company (one who would install high up on the side of the house), it was thousands and thousands more than octopus.

Sticking a heat pump high up on a wall probably isn't a very good idea for two reasons.

1) You probably need planning permission which would add to the cost, and it might get refused..

2) Servicing and repair could well involve scaffolding in order to work safely at height. You might get away with a scaffold tower as long as the ground below is clear of obstructions. if not, having to hire scaffolding every time is going to get very expensive.

You also need to bear in mind that the wall will act like a sound board - Any noise generated by the heat pump will be transmitted through the wall and could get annoying for the occupants inside. Resilient mountings will reduce the noise levels but won't eliminate the problem completely.

Mounting the compressor unit at ground level avoids much of the above problems.

Reed_Richards

Here is my electricity usage until February 2024.  I got my smart meter towards the end of August and moved to an EV tariff near the end of September.  I have done a calculation based on having another 15 kW of usable battery storage, charged overnight, and calculated how much total stored energy I would use each month, assuming the battery is recharged overnight.  Then I have worked out a saving based on 20p per kWh.

	Single	Night	Day	Battery (kw)	Diff	Saving
August	32.332			15
September	197.158	74.342	15.239
October		679.547	205.738	7.262	198.476	£39.70
November		644.819	465.484	93.222	372.262	£74.45
December		568.578	653.788	238.806	414.982	£83.00
January		703.76	582.556	154.838	427.718	£85.54
February		676.858	330.932	36.244	294.688	£58.94

My total saving to the end of February would be £341.60.  I am missing some data for March so cannot take the calculation forward.

Here is the same data assuming I had 20 kW of usable battery capcity

	Single	Night	Day	Battery (kw)	Diff	Saving
August	32.332			20
September	197.158	74.342	15.239
October		679.547	205.738	2.262	203.476	£40.70
November		644.819	465.484	49.974	415.51	£83.10
December		568.578	653.788	154.441	499.347	£99.87
January		703.76	582.556	61.392	521.164	£104.23
February		676.858	330.932	16.654	314.278	£62.86

The total is now £390.7; better, but not that much better as I have hit the law of diminishing returns.

Here's with just an extra 10 kW usable

	Single	Night	Day	Battery (kw)	Diff	Saving
August	32.332			10
September	197.158	74.342	15.239
October		679.547	205.738	20.439	185.299	£37.06
November		644.819	465.484	192.814	272.67	£54.53
December		568.578	653.788	359.976	293.812	£58.76
January		703.76	582.556	283.661	298.895	£59.78
February		676.858	330.932	82.476	248.456	£49.69

Now the total saving is down to £259.80