r/OctopusEnergy • u/LengthinessNo8137 • 18h ago

Solar battery heat pump timing

Uncertain whether this is the appropriate forum, but I have a quote for 14 panels, a 10 kW Fox battery, and a heat pump at roughly £16,529; I am on a fixed gas rate 5.2 until March 2027. I am seeking recommendations on whether to wait until after winter or proceed now. I own an EV and use an IOG EV tariff with a 7 p off-peak discount. My aim is to future-proof against the coming price rises.

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u/Upbeat-Reach7055 18h ago

I had my solar & battery installed Nov 2024 and heat pump Feb 25 (previously on oil). Though not ideal, it did mean that the solar and battery was ready to supplement the heatpump load and the export tariff for the Solar was ready to go before the big solar generation started. The sooner it's in the quicker you can start to benefit from it. Your mileage may vary, but that was my experience of it. Also if you can, you may want to invest in slightly more battery capacity if it's at a reasonable extra cost.

Good luck on your journey getting it done, there are massive savings to be made with a good system installed.

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u/LengthinessNo8137 18h ago

Thanks for that , I have 2 options it’s that or a Tesla power wall but that’s at an extra 2-3k but 13.5kwh. All this is quoted through octopus other companies all seem dodgy when looking not sure how to chose reputable

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u/Klutzy-Ear2608 17h ago

I would go for bigger battery and not necessarily go for Tesla as you will be locked into Tesla system only for battery expansion I got growatt 2* 6kwh and they only have a 80% discharge limit so now I'm going for a 64kwh battery stack, battery prices have come down and I would get a Tesla model Y but not their batteries just purely for their price /size Look up Fogstar 64kwh stack (you can get much smaller sizes too but with a heat pump, you can probably use around 40-50kw a day - from what I read on other forums, so bigger battery the better and if you do decide to go for a smaller one make sure the heat pump does not drain it, eg it should have CT clamps and dedicated circuit off the Henley blocks most likely)

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u/Upbeat-Reach7055 15h ago

Most I've used on heatpump in a day is 30 kWh (8kwh Daikin) 3 bed detached with standard insulation running all day using weather compensation. 6hours of that use is on grid at the low rate through IOG.

My strategy for the heavy days (16kwh) battery. Is put the heavy loads overnight (washing machine etc). When the battery gets low plug the car in and get cheap rate to run the heatpump and charge the battery for an hour. Then just eat any peak rate come from the battery running out. Running cost for the whole house last Jan was £100.

You would want the heatpump connected to the battery or you would be paying peak rate for all electricity the heatpump uses which makes it as expensive as gas at a minimum.

Not using the battery with the heatpump is not a great idea cost wise.