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stumbling goat

Solar PV, Eco 7 query


I hope that someone can help me get my head around my problem?

Have a property that is all electric.

It has 2 night storage heaters, immersion tank with 2 elements. Instant shower over bath. Usual kitchen fittings and appliances, sockets etc

As a result of a meter reading recently, the meter reader pointed out that if I connected the bottom immersion to my Eco 7 I would get a tank full of cheap rate hot water every night. Sounded sensible so I moved the immersion feed to the Eco 7 meter.

On testing the feed I found that it went live at random times, during the afternoon and early morning, but not at Eco7 times. Checked with the Electricity Company and they tell me I do not have Eco 7.

Instead, I get 2 periods of cheap electricity during the day.

Sorry it is a long post but, should I go back to an Eco7 meter?

Does the PV system supply the power to heat the water during the day, or would I be better off having that Eco7 night rate power do this?

Would the night storage heaters be cheaper being powered up at night?

Then the room temp topped up with the built in electric element in the evenings?

I have struggled with this conundrum fort a while, and not sire what to do.

Any informed thoughts welcome?

thank you


First step would be to find out exactly when you get your two batches of cheap electricity. Then find out your unit costs and the unit costs of E7 (it's cheaper at night but more expensive during the day).

It also might depend on how you live, if you're an early riser then E7 is goon IMHO but if you're up late it gets a little chilly.

It will also depend on your hot water / heating split, I would guess that in winter you're not get much solar PV and that's when you want the storage heating.

Probably your current set up in the summer months and E7 in winter!

Oh, and it might depend on your storage heaters, I gather modern ones are more flexible.
stumbling goat

Thank you very much for the reply.

That is my problem, too many angles or aspects to consider.

I will start working those costs out.

Not sure I can change my meter set up every 6 months?

Can change the immersion as that is only a cable re route.

I do know that the PV FIT tariff income dropped over the winter months.

The NSH are modern, and both have a built in additional electric heater option to boost room temperature.

Thank you once again.


Thank you very much for the reply.

Unfortunately I don't have any solar experience so not much help.

I'm trying to think where you get get some good advice, i know there's some out there who are just interested in sales...

I was speaking to an EPC assessor yesterday and he seemed to know a fair bit. Some electritians also specialise in solar.

With all the green money sloshing about you would have thought there is a government scheme advising people - have you looked?

Look up EMMA type units.

They divert any unused elec to your immersion heater instead of exporting them.
stumbling goat

Thank you Richard,

I will start looking, and get one on Tuesday.

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