Advice for relative who has just bought electric only house and wants to optimise
Hi all,
I’ve been trying to give some advice to a relative who has just moved into their new home, and I want to run my thoughts past a community of people who will know more than me (particularly when it comes to heat pumps).
The house is a detached 4 bed in the north of England, entirely electrically powered (with heating being the main issue).
The house is nice and warm, but they have been in for 2 weeks and have used 1,000kwhs of electricity, costing about £250. It has been quite cold for this time of year, including a day of full heating to warm a house which was previously empty, so I’m assuming that’s not far from how their typical winter usage would be. They don’t have any more accurate estimated numbers for winter electricity usage.
They intentionally saved a good chunk of money to do solar etc, and their main aim is not necessarily a return on investment, but minimising their bills going forward (without compromising on the temperature of their home).
Octopus have given them a quote for 19 panels + 13.5kwh battery, no heat pump. However, in order to maximise the house’s efficiency I’ve suggested a heat pump would be very beneficial, and doubling up the battery to get 27kwh would likely be very effective.
Can someone please check/challenge my rationale: The daily consumption has been approximately 70kwhs, so I’m assuming c.50 of that is heating. My understanding is a heat pump could reduce that to c. 1/3rd. (Is that reasonable?), which would bring their daily usage down to somewhere like 35kwhs. On the coldest/darkest months, they probably only make 2-3kwhs of solar per day, so it would be a case of filling the batteries at night on a cheap tariff (one third price for example), and use that all day. I’m assuming this reduces their bills by a huge factor. Eg half the usage, 1/3rd cost overnight, reducing their bill by a factor of 6, and that’s without factoring in the electricity generated through summer and exported.
Questions:
Are any of my assumptions way off base here?
Does the idea of the heat pump make sense? Is this the most important of the 3? (The house is well insulated, but I know they may need to upgrade some radiators)
What would you expect the total cost to be? For 19 panels + one battery they have been quoted £15.9k. Is that reasonable, and what would you expect the cost to be to add heat pump and an extra battery (Tesla PW3).
Are there any potential government grants to be had? They are not on benefits or anything like that, and I believe heat pump grants are only to replace gas boilers, so not applicable here? Just confirming my assumption that there aren’t.
Any other options? I’ve also mentioned the potential benefits of smart radiator valves to not heat empty rooms etc.
Thanks all, I know there are likely people in this community who have done something very much like this, so I’d love to hear about people’s experiences and advice.
Cheers