Solar panels and storage heaters question, 11 August 2022 at 5:01AM in LPG, heating oil, solid & other fuels 6 replies 320 views

gord115

If I were to have solar panels fitted would I be able to replace 2 of my downstairs radiators replaced with electric storage heaters?
I would fit them with 3 pin plugs and timers and heat them during daylight hours.
When all the house needed to be warm I would use my gas central heating for the rest of the house.
How many watts does a typical Storage heater need to heat up?
Thanks in advance

lohr500

Someone with more experience of solar panels can hopefully give you a better answer, but here are my thoughts :

The mid sized QM100 Dimplex Quantum storage heater is rated at 2.2kW input, with a maximum storage of 15.4kwh.

https://www.tlc-direct.co.uk/Technical/DataSheets/Dimplex/Quantum.pdf

I presume from this that if the storage heater needs a full charge of heat it will need 2.2kW input for 7 hours.
To charge two of them you would need to provide a 4.4kW supply for 7 hours.

I think the size of the solar panel array needed to generate a reliable continuous 4.4kw output on cloudy and short winter days would be well beyond the scope of most domestic installations. I have seen figures that suggest on overcast days, panel output can be as low as 10% of the maximum. I imagine the cost and space requirements to install a 40kW array would be very great.

Plus, unless you had the storage heaters on a dedicated circuit from the solar panels, they would be competing for electricity with any other devices drawing power through the day.

By the time you have bought all the kit needed, I am 99.9% sure it would make more sense just to keep the central heating radiators in those two rooms.

However, those with actual solar panel experience will hopefully be able to quantify the space/cost requirements.

mumf

Plus,when you really need storage heaters - Winter - there isn’t enough sunshine/ intense light. 

Dolor

mumf said:

Plus,when you really need storage heaters - Winter - there isn’t enough sunshine/ intense light. 

Exactly, I have a 6.35kWp array. My generation in December was 110.3 kWh with daily outputs ranging from 10.3kWh on a bright and sunny day to a low of 350Wh.

gord115

Thanks everyone. 
Thinking about it, if it was a good idea more people would be doing it.
Cheers.

Bendy_House

When I had my PV system installed - ooh - 9 years ago?, along with a Wattson meter, I behaved like, I suspect, most folk with a new toy. Especially if it saves them a few pennies.

So, I found someone storage heaters on ebay, and bought around 5 of them for a £iver...

First lesson - the car's suspension won't thank you.

Second - getting rid of unwanted SHs ain't much fun - there are still some bricks being used as outdoor plant pot holders.

Anyhoo, I wired one up to a 13A plug (I know I know - but it was well within its rating), and would flick the switch whenever the Wattson gave me the 'go'.

I remember the chuckle as this old SH was brought to a sizzling temp at no cost! The only issue being that it was a bright sunny day and it was already sweltering inside.

All of the above is a digression.

In principle, this IS a good idea. You might not be able to fully charge the heaters every time, or anything close, but anything you DO get in to them will contribute to that room's heating, and will reduce the amount of supplementary heating required.

What I would suggest, tho', is to fit a PV controller - there are lots of them available - which will automatically divert ANY surplus leccy to the SH. These are often used to charge up hot water tanks, but they should work just the same for SHs.

This would mean, tho', that you'd need the SH in the room in addition to the existing wet rads. And it would also mean a ~£250+ outlay for the controller. If you keep an eye on Facebook Marketplace and eBay, you might pick up a suitable SH for next to now't.

Absolutely your call whether it's worth it, but there is also no reason why the SH couldn't be dismantled and stored in the garage come the warmer weather.

At its best, there should be no 'surplus' leccy going to waste. And winter sunshine still occurs :-)

Bendy_House

http://www.totnesenergy.co.uk/solar-immersion-controller-review/

You'd need to confirm that these could be used to charge a single ~3kW SH.