Storage heater KwH usage

dekkard

I've been trying to help my elderly Mum get her electric bills down for her flat.

She only has electric, no gas. She has storage heaters, an immersion heater, all on Economy 7. She's with Eon on a fixed tariff.

Having done two meter readings 10 days apart, it seems she's using around 31 KwH every night (!) I had set the immersion heater timer so that it comes on for a couple of hours at night during the Economy 7 time.

But I can't account for why her two storage heaters are consuming SO much electricity every night. The input isn't at Maximum. Could they just be old and super-inefficient?

footyguy

dekkard wrote: »

I've been trying to help my elderly Mum get her electric bills down for her flat.

She only has electric, no gas. She has storage heaters, an immersion heater, all on Economy 7. She's with Eon on a fixed tariff.

Having done two meter readings 10 days apart, it seems she's using around 31 KwH every night (!) I had set the immersion heater timer so that it comes on for a couple of hours at night during the Economy 7 time.

But I can't account for why her two storage heaters are consuming SO much electricity every night. The input isn't at Maximum. Could they just be old and super-inefficient?

What makes you think that is high?

Remember, with E7, ALL the electricity consumed during those 7 hours are charged at low rate.

But ignoring that, if we assume the immersion heater uses 6kWh (2 x 3kW) for the 2 hours it is on, that leaves just 25 kWh spread over 2 heaters.

That's almost the same energy that a single bar electric heater would consume if left on all day. (which you would need to because that type of heater only outputs heat when it it on, whereas a NSH obviously stores heat, emitting it slowly, to keep you warm the whole day)

lstar337

I'll start with the tank. If it is properly insulated (or has a jacket) then it won't lose much heat over the E7 period. Reducing the heating time to 2 hours will save you little to nothing. It also increases the risk of Legionella bacteria growth within the tank that would be particularly bad for an elderly person with a weaker immune system.

Storage heaters come in several sizes, but if she has two big ones then they can pull in a lot of units overnight. The bonus is that all of that goes towards heating the building, 100% of it.

If you want to reduce bills then you are going to have to look at her day/night mix and see where you can trim the fat. Day usage is much more expensive than night, so if you can shift any of that then do so. Any other heat source used during the day will push the price up a lot.

Lastly, make sure your tariff is competitive.

NineDeuce

It might be at the low rate but electric heating is still horrendously expensive. 31kWh per night though... does she need this every night?

Robin9

Don't skimp on keeping your mum warm - she will be paying a little over £2 a day for this during the winter and she's getting a heating grant of £200 as well (so that covers 3 months)

Have you used a comparison site to see which is the best tariff >

lstar337

NineDeuce wrote: »

It might be at the low rate but electric heating is still horrendously expensive. 31kWh per night though... does she need this every night?

Your post shows you know nothing about night storage heating.

With a good tariff, night storage heating can be close to the cost of gas central heating, the cheapest of all sources. The downfall is that it isn't as controllable.

And yes, it has to be on every night that you require heating the next day.

ProDave

So 31KWh each night, less 6KWh for the immersion = 25KWh for the heaters or 12.5KWh each

The bigger storage heaters have 3KW heating elements, so a single large storage heater can use up to 21KWh each night so 12.5KWh sounds quite resonable.

There is no easy answer to reduce cost.. Go cold, or move to better insulated house (or improve the insulation of the one she has)

That is still costing less than £2 per day for heating.

poppasmurf_bewdley

I have a 3Kw storage heater in my lounge which has been on for the past few weeks.

It, together with my electric immersion heater, use 17 units per night, which at 7p a unit costs £1.19.

For that I get full heating in the lounge from when I get up at 8.30am until I go to bed at approx 11.15pm, and all the hot water I need.

I call that good value for money.

NineDeuce

lstar337 wrote: »

Your post shows you know nothing about night storage heating.

With a good tariff, night storage heating can be close to the cost of gas central heating, the cheapest of all sources. The downfall is that it isn't as controllable.

And yes, it has to be on every night that you require heating the next day.

Thanks for the mildly patronising although groundless assertion of my knowledge.

Lets do some facts then....6-7p/kWh v 3-4p/kWh. Add to the fact that even by your own admission, it isnt as controllable. So either.... we didnt need as much heat as was stored, then it becomes 6-7p/kWh v 0p/kWh.... or..... lets say that we need further heat than what was stored at night, then it becomes 13-14p/kWh v yes, you guessed it 3-4p/kWh...

So the fact that the unit rate for gas is cheaper and that I can turn it off when I want and not have to leave it on all night, what part of what I am saying is incorrect?

lstar337

NineDeuce wrote: »

Thanks for the mildly patronising although groundless assertion of my knowledge.

It isn't groundless, the evidence is right in your post.

NineDeuce wrote: »

what part of what I am saying is incorrect?

This part:

NineDeuce wrote: »

does she need this every night?

If you knew anything about Night Storage heating, you would know that charging is needed every night for which a day of heating is required. This is how the system works.

Note, I didn't attack your knowledge in general, just your knowledge of Night Storage heating. None of your maths exercise changes the inaccuracies in your earlier post.

Please also note, that when you account for the inefficiencies of burning gas coupled with the maintenance cost of a boiler and wet distribution system, plus the cost of running the pump, it is in fact very close to a properly configured Night Storage system in terms of running cost.