Storage heater cost help!

Jersey497

I had really old storage heaters in my flat when I moved in last month. I have no experience with storage heaters at all. I have just had them replaced. They are brand new and the modern version with the electric controls.

I had the switches on 2 nights ago to charge them for the first time with the heaters being set to 21 degrees as default, and I have just checked my electricity app and it has cost me £7.88 for one night of charging the heaters on economy 7 tariff, saying I’ve used 33kwh of electricity. One is a small one in my hallway and the other is a medium in my living room.

How is this possible??? I was told that if I charged my storage heaters up overnight which I did, then I wouldn’t be charged at all for having the heating on during the day, because the heat had already been charged up and stored using the cheaper electricity rate overnight. The electrician that came to fit them said I should be looking at average £3 per night on the economy 7 tariff. 

I am not going to be able to afford almost £8 a day going forward. Especially. when I’m on the economy 7 tariff I just can’t and don’t understand why is it costing so much? Does it really cost over £7 to charge 2 storage heaters on economy 7? 

I don’t understand how it is so expensive. Please help! And any tips to reduce cost, thank you! 

Netexporter

Once the fabric of the building has absorbed enough heat to reach near equilibrium with the inside air temperature the amount of energy required will reduce. It is the same for any heating system. You could also turn the thermostat down a degree or two. The rough rule of thumb with central heating systems is that turning the thermostat down by one degree saves 10% of fuel.

lohr500

Do you know the model numbers of the two storage heaters?
And based on the 33kW / £7.88, this would suggest a rate of £0.239 per kWh. £0.239 sounds high for off-peak Economy 7. What are your latest Eco7 peak and off peak rates? Are you sure the App is showing the correct unit cost?

Swipe

Those numbers you were told sound extremely low. I doubt the electrician uses them himself. I have 4 storage heaters of differing sizes here and I'm currently using around £8 a day on a night rate of 13.02p and three of those are on to only heat the rooms up to 14C. I'll no doubt be looking at well over £10+ a day this week as I've had to turn them up ready for the upcoming cold snap and I'll be lucky if my living room stays above 16C by mid afternoon.

Jersey497

Netexporter said:

Once the fabric of the building has absorbed enough heat to reach near equilibrium with the inside air temperature the amount of energy required will reduce. It is the same for any heating system. You could also turn the thermostat down a degree or two. The rough rule of thumb with central heating systems is that turning the thermostat down by one degree saves 10% of fuel.

Great thank you! I’ve had them on 21 because that’s what the default was but I will turn them done to 18 and see if that helps. 

Jersey497

lohr500 said:

Do you know the model numbers of the two storage heaters?
And based on the 33kW / £7.88, this would suggest a rate of £0.239 per kWh. £0.239 sounds high for off-peak Economy 7. What are your latest Eco7 peak and off peak rates? Are you sure the App is showing the correct unit cost?

The brand is quantum and the model number is QM125RF for the living room and QM070 for the hallway. I need to call Utilita in the morning because it doesn’t actually tell me what my economy seven price is, it’s just telling me that it’s 84.3p for the first 2kwh of energy used per day and then 32.2 for the rest. It doesn’t say anything about the overnight price 

Jersey497

Swipe said:

Those numbers you were told sound extremely low. I doubt the electrician uses them himself. I have 4 storage heaters of differing sizes here and I'm currently using around £8 a day on a night rate of 13.02p and three of those are on to only heat the rooms up to 14C. I'll no doubt be looking at well over £10+ a day this week as I've had to turn them up ready for the upcoming cold snap and I'll be lucky if my living room stays above 16C by mid afternoon.

I will try to turn them down to 16 or 18 and see if that helps with the price. Thank you! If I had known it would’ve been less of a shock

Swipe

Jersey497 said:

lohr500 said:

Do you know the model numbers of the two storage heaters?
And based on the 33kW / £7.88, this would suggest a rate of £0.239 per kWh. £0.239 sounds high for off-peak Economy 7. What are your latest Eco7 peak and off peak rates? Are you sure the App is showing the correct unit cost?

The brand is quantum and the model number is QM125RF for the living room and QM070 for the hallway. I need to call Utilita in the morning because it doesn’t actually tell me what my economy seven price is, it’s just telling me that it’s 84.3p for the first 2kwh of energy used per day and then 32.2 for the rest. It doesn’t say anything about the overnight price 

Definitely get the day and night prices from Utilita and you should consider switching to the cheapest supplier with the best overnight rate (baring Utility Warehouse of course )

Scot_39

A medium sized modern NSH can probably store c 20kWh of energy (QM125RF - 19.3 kWh - the larger QM150RF - 23.1kWh) - a smaller one c10kWh (QM070RF - 10.9 kWh) - add on a normal day of 5-10kWh for everything else -  the initial charge. (With gas - duel fuel tdcv - medium - single rate electric TDCV is 2700 kWh = 7.4kWh / day).

Some modern will charge to 80% (Elnur default iirc or was it 90%) initially and then adapt from there depending on demand - if intelligent adaptive algorithms enabled.

0.8x30 = 24 + 8 = 32 kWh - so your 33 kWh really not a silly daily day 1 number.

And you have to actually heat the structure of your home - not just the air.

Even on older models - you have to heat the bricks in the heater before they start to heat the home - and when you heat the air - the air is heating everything in the home - including walls and furnishings.

My old heater consumption peaks after first switch on - and then settles down over a couple of days - as losses to a warmer home - reduce demand. Tweak the input (essentially core brick temp demand) down - electric demand drops notably first day then recovers - turn it up it peaks a little again for a day then settles.

Last Dec when I returned to a cold home after a week away (minimum heater settings had kept house at c12C) - on the first day of the bitterly cold snap - my first day power use was 32.6 kWh as switched heaters on / others up - it then dropped to c27 kWh next day and settled c24kWh a few days later.

And that was only aiming for 17 max LR / 15 max elsewhere.

Tweak those C targets up - even just 1 or 2 C - can add 100s kWh / if not 1000s kWh - annually.

QrizB

Jersey497 said:

lohr500 said:

Do you know the model numbers of the two storage heaters?
And based on the 33kW / £7.88, this would suggest a rate of £0.239 per kWh. £0.239 sounds high for off-peak Economy 7. What are your latest Eco7 peak and off peak rates? Are you sure the App is showing the correct unit cost?

The brand is quantum and the model number is QM125RF for the living room and QM070 for the hallway.

A Quantum 125 will store ~20kWh. A Quantum 070 will store ~11kWh. So 33kWh doesn't sound too far off the mark.

Jersey497 said:

I need to call Utilita in the morning because it doesn’t actually tell me what my economy seven price is, it’s just telling me that it’s 84.3p for the first 2kwh of energy used per day and then 32.2 for the rest. It doesn’t say anything about the overnight price 

In my region, Utilita's E7 tariff looks like this:

That is a poor tariff for anyone with storage heaters who expects to use far more off-peak electricity than peak.

Octopus for example are offering this:

If we imagine that you are going to use 5kWh/day of daytime electricity and 20kWh/day of nighttime, Utilita will cost you £6.79 a day. Octopus will charge you £5.38 for the ssme eletricity.