EDF Economy 7

tinaxania

What is the 7 hours of economy nightime use for EDF in Clapham,
South London ? I cant find a website with the actual start and finish times. :wave: Thanx

Cardew

Nowt to do with EDF. From their website.

Night kWh will be supplied for a total of 7 hours between 10pm and 8am (actual times set by the local network operator) and these will be charged off the Night kWh ratev.

For instance if you changed from EDF to BG to EON the switching time would remain the same.

I believe you will find for London the times are 11:30pm to 6:30am BST so at the moment 12:30am to 7:30am.

That is if you are switched remotely to E7. Many are still switched by a mechanical clock and over the years these can be fast or slow by a large margin - some have reported on MSE they get all 7 hours during the day!

tinaxania

At the moment, the timer switch to turn on the immersion heater at night is not working. Hasn't been for a few weeks now. An electrician has been to fix it, couldn't do it and is now sending a plumber. What I'd like to know is -
- I use the boost switch to heat up the water - I get up at night about 4am leave it on and switch off by 8.30, (I thought that was the cut-off for off-peak) apparently it's not, BUT is it still cheaper for me to use the boost switch during the 7 hours, for a coupla hours only, or do I need to get the timer switch fixed. Are there two different elements in the boiler (as told to me by the electrician) so costing more to use the boost, or am I saving by over-riding the timer and putting on the water for fewer hours ? Sorry so long winded...

Cardew

Some houses have all their electricity at cheap rate for the 7 hours - lights, sockets, immersion etc. Others only have the immersion heater(and storage heaters if fitted) switching on for 7 hours in the night.

If you have a timer for the immersion, it sounds like you have all electricity on E7. You can check this by looking at your meter during the 7 hours when you put on a kettle and see what display is moving.

The immersion should heat sufficient water to last all day in a couple of hours at the outside. It is obviously cheaper to have the immersion heating during E7 hours.

It doesn't matter if you leave the immersion on for a couple of extra hours after all water has heated because the thermostat will have operated and you won't use any more electricity.

Some hot water tanks have two immersion heaters, the main one heats the whole tank and a smaller one that heats the top of the tank and is used during the day to top-up if you run out of Hot water.

Lastly if you don't have storage heaters, it may be cheaper for you to change from an E7 tariff to a normal 24/7 tariff. The reason is that you pay a premium for the 17 hours daytime supply when on E7. Therefore the extra you pay for 17 hours may be more than the savings during the 7 hours of cheap electricity.

tinaxania

A great help, Cardew, thanks so much (again)! I am all electric, no gas, with storage radiators (for my sins).. and now a greater understanding of the workings of E7.. I will keep turning on the water for a few hours at night, until they fix the timer. During the winter months, I'll just let the timer do its stuff for the full 7 hours, it does not stay hot long enough otherwise. I will get more lagging tho. Thanks for you help. :T
(Are you any good with laptops???)