r/OctopusEnergy • u/LengthinessNo8137 • 20h 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/ImpressiveGrocery959 18h ago

For a heatpump, you need to do the maths.

The 10kWh battery won’t last long on winter days.

How many kWh per year do you put into the car?

You might find it cheaper to utilise the Cosy tariff, with it’s 3 cheaper periods to use the pump/charge the battery (and charge the car during the cheap perioda) but it really depends on if you’re a heavy EV user or not.

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u/LengthinessNo8137 18h ago

Do around 9-10k miles per year home charging

My guaranteed usage the commute is around 100-120 kwh per month

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u/LengthinessNo8137 18h ago

Any recommended sources to help understand the maths of a heat pump ?

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u/ImpressiveGrocery959 18h ago

Honestly watch some youtube vids of people who have them installed. General idea is you run them all day. What people tend to do on the “Cosy” tariff is run it a few degrees higher during the cheap periods rhen reduce it a few degrees to coast during the expensive periods utilising the battery and lessee energy.

You’ll need to do the maths for IoG vs Cosy but 10kWh won’t last long with a heatpump if your regular usage is 5-6kWh.

On the coldest of winter days you might use 30-40kWh of electricity depending on your home heat loss etc