Economy 7 / 7am cheap rate

WiserMiser

Just a quick history lesson. The original 'cheap overnight' scheme (in SE England) was the White Meter. Yes, it was painted white and had a separate clockwork timer automatically wound up from time to time by electricity. They were originally eight hours but it was found that seven was usually sufficient and so Economy 7 was launched.

That mechanical timer naturally led to 'always GMT' but that's a definite benefit if you have an immersion heater on a 24h circuit with your own local timer. You don't have to worry when the clocks change, you just have to make sure that both timers are synchronised (could be 15 minutes before or after the nominal time). Don't use a mechanical rotary timer because a power failure will make it switch at the wrong times.

Note that the times are determined by your DNO, not by the company whose bills you pay.

Section62

https://forums.moneysavingexpert.com/discussion/comment/82009484#Comment_82009484

…and had a separate clockwork timer automatically wound up from time to time by electricity.

AIUI the 'clockwork' timers used were always powered by a synchronous motor, with an electrically wound spring reserve (clockwork) to keep the clock running (for a limited period) during power cuts.

The advantage of using a synchronous motor is that the clock will keep accurate time with very little drift, whereas pure 'clockwork' timers will drift unless very accurate (aka 'expensive') and operated in stable conditions (e.g. temperature).

AIAUI the grid was (not sure if it still is) managed so that any net deviation in the 50Hz frequency during the day (caused by variable supply and load) would be removed by deliberately altering the grid frequency in a managed fashion so in normal operation each calendar day had 4,320,000 cycles and a synchronous motor timer would therefore remain sub-second accurate (to whatever time it had been set to initially). These timers were relatively cheap because the accuracy was provided by an external source, not by the timer itself. For this reason they were a popular choice for streetlighting controls.

johnweir123

Why would anyone want the overnight rate available until 7am? Because I have a 10kw electric shower and if we get our showers done before 7am (which is easy) then that saves quite a bit on the daily electric bill. Before 6am is trickier and before 5am is nearly impossible unless you're really weird.

Scot_39

I still think you might be confusing E7 - a traditionally register based billing system - even on older digital - and even today I suspect on smart meters - and other more modern 1/2 hourly billed multirate TOU tariffs designed for EVs or other forms of electric heating - like Cosy tariffs etc.

0700 and 0730 are the most common E7 end times - and of course - as thats traditionally fixed GMT - allows an extra hour for showering in summer (0800 and 0830 DST)

I don't remember from posts here any standard E7 tariffs that don't follow the GMT rule - but I do know of many smart and EV tariffs that follow clock time rigorously (so there would be no summer sleep in - schedule permitting etc - for getting a cheap shower in).

Some of the alternatives - if they suit you heating (if it needs meter switched restricted power they probably wont) - might though work out better than E7 - given the heavy peak rate loading to pay for the off peak. Some give cheaper than E7 night (for sometimes only 3 or 5 hours) and "most of day" rates - but also have a sting in their tails - very expensive rates say 4-7pm (peak grid loading time) - and you need to be able to "avoid" any significant use in those windows.

I am however not 100% convinced all suppliers are quite as tied to the old DNO windows as they were back in the days of the old electricity boards - as many - like say largets for now Octopus - now only quote 1 fixed set of times on their user blogs / FAQs etc - for the whole of the UK.

Out of interest - which tariffs were you looking at for 6am and for 5am end points ?

(Im on E10 for instance (3 off peak 1-4pm, 8-10pm and midnight to 5am - all GMT) - but AFAIK - Ovo are the only ones offering that as an open tariff - at least to those currently on E10 for online quote tool.

But yes your point about getting heavy use "loads" in during off peak being key to lowering costs is a very important one to be aware of when choosing any tariff.

And whilst many concentrate on winter heating - hot water heating - an all year round cost - is often right up there (I'd say mines beats my space heating use in milder winter years - and thats just for 1).

TroubledTarts

https://forums.moneysavingexpert.com/discussion/comment/82010255#Comment_82010255

Interesting way to go to call strangers weird if they have to get up early for many reasons.

debitcardmayhem

https://forums.moneysavingexpert.com/discussion/comment/82010458#Comment_82010458

Indeed, being a carer is well weird ☹️

GibbsRule_No3

I am with EDF and at this time of year mine does not go off until 8.30 in the morning. 7.30 when the clocks change again. I'm sure that I could probably switch the plug on at 6.00 - 6.30 my hot-water tank would give me enough for a shower (single occupancy) and washing up water for the day, if only I was organized enough. I do find that I put my washing machine on to take advantage of the 8.30 end though.

dunstonh

https://forums.moneysavingexpert.com/discussion/comment/82012137#Comment_82012137

We're on economy seven and don't have separate circuits. For everything we want to go on the off-peak rate, we use timers. Those timers remain at GMT all year round and do not change for BST.

Back to the op. The cost of a shower running at peak times is insignificant in the scheme of things unless you've got an electrically heated shower. If yours draws from the hot water tank and/or uses a water pump, then the actual electricity used is low. It's only if the electricity is used to heat the water that the use becomes very high.

QrizB

The cost of a shower running at peak times is insignificant in the scheme of things unless you've got an electrically heated shower

OP did say:

I have a 10kw electric shower

A 10-minute shower will take 1.7kWh which would cost 42p at the 25p/kWh SVT but would only be 17p on a 10p/kWh off-peak tariff.

Of course we don't know how much daytime electricity the OP typically uses (hopefully they do and can share that info). A 10p/kWh off-peak rate would suggest a 36p/kWh daytime rate which might obliterate any "cheap shower" savings.

Scot_39

Taking EDF tariff tables and 1st region - and lets assume on average 2x10 min showers a day (the OP iirc said showers from 10kWh) - thats 3.33 kWh - lets round it down to 3kWh to make the maths simple

E7 off peak 13.3p, peak 28.6p - so 15.3p diff x 3kWh - 46p/day - £168/year.

Other suppliers are far more aggressive on their E7 tables - iirc those complaingin about the loss of 6p rates in April at was it UW - were still sub 10p - so the difference could be even greater.

Even if that £168 was halved - I'd say for most folk - still a useful saving.