Night Storage or Electric Radiators?

Robbie_Macca

EachPenny wrote: »

Have you checked to make sure your meter is switching at the correct times - especially if you have 'whole house' Economy 7 and any of the heaters are controlled by their own separate timer.

Older E7 meters use a mechanical clock which can drift so the E7 hours are not during the night. If that is the case for you then you might want to think about getting the clock changed... or not (just ensure your heavy consumers are operating during the hours the meter is on low rate)

If you have a separate distribution board for E7 (not 'whole house') then make sure the main heating element on your hot water cylinder is fed from that one.

Silly question, but if my washing machine is connected to my main distribution board, will it use the cheap rate during E7 hours or not?

Yes the water tank is connected to both the distribution boards,.

Owain_Moneysaver

Robbie_Macca wrote: »

Silly question, but if my washing machine is connected to my main distribution board, will it use the cheap rate during E7 hours or not?

Yes, on standard Economy 7 tariffs. Possibly not on Total Heat, White Meter or some other 'legacy' tariffs.

One thing you might want to consider is upgrading your hot water cylinder to a larger one. Are you using peak rate boost? 180 l isn't huge for 4 people - and don't use an electric instant shower at peak rate instead of the stored hot water!

I think you should be able to get more usage onto off-peak tariff.

The other thing to look at is insulation of course.

Richie-from-the-Boro

Your E7 water heating should be PartL compliant meaning the unvented cylinder is much more heavily insulated and the E7 system is wired [isolated] through a Water Controller something like this :



You will know if the water is wired the wrong way round by holding the bottom insulated cable after midnight. The element is 3kW and will be very warm to the touch within minutes of beginning to charge.

Additionally the NSH damper should be tight closed and never opened all year to return the best day/night ratio. If you need to open a damper you have an inadequate STORE of cheaper heat and need to up-size the NSH.

So if your average E7 was ≈ 50/50% over 12 months @ about 4k kWh of day rate and 4k kWh of night rate, a total annual mixed consumption of 8k kWh, and assuming 70% of the total night rate being consumed in the winter period.

Now all homes and usage is going to be different but if you lived in a typical 80's regulation build, refurbished with typical insulation and current double glazed to a B-C EPC rating and using bog standard automatic model cheepo stoarge heaters @ todays E7 tariff rates it would cost in the region of £8-900 annually, my old 2017-2018 personal projection [see above (29th 2017)was £712.96.

You want an average of 21°C in the winter period and you own one big 3.4kW and one middle sized 2.5kW NSH thats a total of 23.8 + 17.8kWh or 41.6kWh of stored heat. That 41.6kWh of stored heat is available for release over the next 17 day hours or the equivalent of a 2.44kW fire at full output for those 17 hours.

Of course there will always be odd days when you need complimentary extra heat immediately, and days when your store of heat is never fully depleted, but its not wasted but remains in the can [ditto water cylinder] as existing heat that does not need to be replaced the next night.

- Day 2,455 kWh = 41.87% Day
- Night 5,864 kWh = 58.13% Night
- Total-pa 8,319 kWh


Best of luck.