We have been looking at Solar + Battery + ASHP for hot water and central heating.
I get the fact that ASHP provides “free” heat, but direct electric heating looks simpler, cheaper to install, and silent. Noise is a big issue for me.
We are on the Octopus EV tariff so one option could be to charge up electric storage heaters overnight.
Are the finances ridiculous for electric heating? Any thoughts?
When planning new heating, or other energy use, work from first principles. Tariffs come and tariffs go, so don’t give them too much consideration. Having said that, I make optimal use of my tariffs. Flexibility is the thing.
Currently I am on Intelligent Octopus Go, so my off peak is only ¼ the day time rate. I also have solar and battery but unlike you I have a heat pump.
Direct electric heating is easy to install but you will need an electrician to fit one or more dedicated circuits. Adding loads of heating to your existing electrical system is a sure way of overloading it. Also check the rating of your main fuse and add up the rating of all your heating devices. The peak load will be worse if you are loading the heating requirement to the night as you will need to boost house temperature and or storage heaters, presumably plus an immersion heater (or two) for hot water. You would need massive batteries to run direct heating throughout the day.
A modern heat pump uses at worst ⅓ the electricity, so the household system may need significantly less modification.
What is your heat loss/heating demand, in kilowatts? From that you can calculate how much extra current your main fuse will need to tolerate.
Remember that peak solar production is in summer and peak demand is in winter. For the heating season you need to almost disregard the solar contribution and plan a system which for at least 80% time runs on cheap electricity. To meet the other 20% from battery is unlikely to be economical but could perhaps be justified other ways, such as resilience in the event of power cuts.
Thanks Tim, that is very helpful advice as always, particularly the solar summer/ heat in winter point. Direct electric does sound very expensive!
Nicely put. The issue is whether you (or other readers of this thread) can afford a heat pump, taking into account any grants or loans available. Direct electric is in itself cheap but the lifetime cost can lead to fuel poverty.
Assuming you don’t live in a Passivhaus or EnerPHit house.
A Top Tip David, don’t get it all at once! Get Solar in first and then see how much you can actually generate before getting a battery - it may even not be worth getting one. I have solar only and am getting an ASHP installed next week (3.5 years after the solar) and have not bothered with batteries. Given I have 111kWh of mobile batteries (EVs) sitting on my drive I am waiting for Vehicle to Grid to materialise rather than spend £10k on even more batteries!
I too took a gradual approach. It certainly helps affordability, particularly as tech prices tend to fall with time, although labour goes the other way.
I bought solar in 2005, then more solar and a battery in 2017 for less than the smaller solar only system cost. Then in 2023 I bought another battery and a heat pump.
Thanks for these useful contributions.
I am currently thinking of using the Octopus offers, they suggest doing the heat pump first then I get 10% off for solar and battery at a later date.
I’ll check out the site for any thoughts on Octopus before plunging in.
That looks like a good deal but does mean your home needs to suit the Octopus one size fits all approach.
It isn’t strictly one size as the heat pump varies but everything else is fixed.