Solar panels

[PalmTreeDevon]

We are looking to buy a new build house on an estate where all the houses have solar panels as standard. Obviously we are hoping this will reduce our energy bills but I am unsure how much it might actually make a difference particularly as there is no battery for power included. Has anyone got any experience on this and whether it's worth paying for a battery when you buy new build?!

It depends on your usage of the house and the size of the array installed.

Some builders will install minimum panels that don’t meet the energy requirements of the property size.

if you are out a lot in the day a battery is worth considering.
There is zero VAT on battery installs until 2027 you may find it cheaper to contract the solar installer directly after purchase instead of going through the builder.

If I were you I’d move in and monitor the generation and what exports / imports over a period of time and decide about the battery later.

For more in depth data if the array doesn’t come with the dongle to connect it to an app that would be a worthwhile purchase. You will then see how and when you are using the electricity generated.

Are they 'your' solar panels?

Some people have leased out their roof for the benefit of the solar panel installers - and you would want to be wary of that.

I don't know if building companies have done this... yet.

Not a new build but we have solar panels with a battery. We sell excess electricity to the grid for about 15p but have to buy it for 23p if we don’t generate enough to cover our usage. So in my view it’s worth having the battery because it costs us more to import electricity than we get for exporting it. Most of our electricity generation happens during the summer and during the day, whereas most of our energy usage is in the evening and winter when it’s darker. We essentially pay nothing for electricity between May and the end of September (unless it’s a particularly dismal summer!) and then what we’ve sold over summer mostly balances out our usage over winter.
We have a gadget added on that means the solar heats our water when there’s enough generation too, which is great as we’re on oil otherwise.

But I agree that for the moment it might be worth seeing how it works for you without the battery for a bit first.

Do you have gas as well?

You'd need to try and maximise your usage of electricity as it comes in so dishwasher on, washing etc in the middle of day. Easier if you WFH some days.

If you are a tumble dryer user then it will be useful. The trouble is the best days for this are the ones you don't need it because you can peg out (but aware not everyone does).

You need to go with Octopus to get 15p a kWh for your export.

On a 5kw system in north Scotland I've exported more than £1 today and that's with an all electric system. It was a great day.

You also have to get used to using within the capacity of your inverter. So better to boil the kettle then turn on the dishwasher rather than doing them simultaneously.

Without a battery you are still going to be paying to run your oven in the evening (assuming electric) as generation won't be strong enough by then.

It also won't be enough for say a 10kwh electric shower which is the biggest expense in our house.

If you have gas then the benefits of a battery are not as great as an all electric system.

I'd expect you to pay virtually nothing for your electric in the summer but it won't be the same every day. Sometimes you might export 20kwh, other days take from the grid. You'll save fairly small amounts October to Feb but it should allow you to have a fairly low direct debit.

If you don't have gas it's nuts they've installed without batteries.