Working out charge for my storage heaters

QrizB

Rosie1001 said:

Would my heaters continue charging for full 7 hours on eco 7 where is it’s all in overnight charge ??.
do they not just take all they can and stop charging 

"All they can" is 24kWh, which is how much they're intended to store (on effect, how many bricks they hold). If they've got 3.4kW heaters, it takes seven hours to fully charge them. 7 x 3.4 = 23.8.

Currently they're only charging for five hours overnight. 5 x 3.4 = 17. So only storing 17kWh.

Adding two hours of overnight charging will mean you store an extra 7kWh.

Rosie1001

Thank you ..

so I if can only get eco 7 initially I won’t be the end of the world … 

then hopefully I can get eco 10 from my supplier or change to Octopus snug 

Swipe

The majority of households with storage heaters will be on economy 7, myself included. I think Octopus Snug will be the most cost effective and I'm planning on switching to that myself in Autumn when my 10.92p off peak E.OnNext fix ends unless I can snag a 9p fix over the summer

Rosie1001

Technically I’m on eco 7 , but split times 

5 hours overnight, 2 hours afternoon 

Rosie1001

On my afternoon boost today my reading are 

96516.  1pm 
96529   3pm 

only had my heaters on and my tv and  fridge freezer ,  I turned everything else off 

lohr500

QrizB said:

Rosie1001 said:

so I do need my afternoon boost

I think those calculations aren't correct and might have given you a wrong answer.

Your storage heaters currently get five hours of overnight charging and two hours of afternoon boost. In total, then, they charge for seven hours, enough to add 24kWh each and last through your day.

On E7 they would get seven continuous hours of charging, enough to add 24kWh each. I don't see why those 24kWh won't last the whole day in exactly the same way as your current 24kWh do.

How much cheap-rate electricity have you used in the past month? What does your latest bill say? How much heat are you actually using?

Yes, I guess I didn't explain my thinking clearly!! And I could well be wrong anyway.

I agree, with 7 hours of heat you can only push a maximum 24kWh into the storage heaters. Regardless of if that is for a single 7 hour block or a block of 5 + 2.

But if all the heating takes place in a single slot from say 12:00 to 07:00 and you are "leaking" some heat during that period because the storage heaters can't retain all the heat transferred from the elements, then won't you be losing heat when you don't want it? With the 2 hour boost later in the day, at least the lost heat is useful. 

As the OP is an early riser, and early to bed, it probably makes no difference anyway!!!

Rosie1001

Yesterday I used 13 kWh on afternoon boost 

overnight I used 31 kWh 

so 44 kWh in 24 hours on my heat charge price 

My home is warm when I get up  at 5 am so definitely leaking some heat 

QrizB

Was any of that cheap-rate electricity used for water heating? You have an immersion heater and a hot water tank?

Rosie1001

All of that was my cheap rate … so my storage heaters and background electric overnight like freezer and fridge  and 2  tv on standby , 2 virgin  media boxes 

everything else gets turned off 

No water heating 

I’ve not took  the other “ normal “ readings 

QrizB

We can probably allow 1kWh during the 5hr nighttime period for "everything else", then (possibly a bit less). Which would mean that ~15kWh went into each of your storage heaters, not far off from the 17kWh each we calculated based on their rating.

And then you put another ~6.5kWh into each of them in the 2hr afternoon period. Again, close to the 6.8kWh we calculated as their nominal capacity.

15+6.5=21.5, less than 24.

It seems likely that, if they'd spent 7hrs charging overnight, they'd have had enough capacity to see you through the day. So you'd probably be OK with E7, if you couldn't get E10 or Snug.

Complicating matters, Snug is cheaper than E7 which is (likely to work out) cheaper than E10 for you. So there's a moderate saving to be had if you can get along with E7 or switch to Snug.