ECONOMY 7 COSTING US LOTS

Aliceinwonderland1533

hi everyone. We have just moved into an all electric property. We are on economy 7 and have storage heaters and an overnight heating water cylinder.
During the day we use between 3-5 units so not bad at all.
Overnight however, we used 36 last night. We had the overnight water heating system on as usual (this is timed that it will only run during the cheap hours, and is a 3kwh immersion heater). We had two storage heaters set to 3 out of 8. And a dishwasher running for 1 hour. 
I couldn't understand how we used 36 units (at a rate of 15.54pp kWh so £5.59) so I worked it out.
Water - 3khw X 5 hours - 15
Storage heaters 3.4khw X2 - heating up for 3 hours - 20.4 units

Dishwasher - around 1 unit.

Unfortunately it's a large property and in the eaves so freezing cold. We have a baby so we have to have SOME heating in the lounge and the one near his bedroom. Even with the two storage heaters we aren't getting temps of more than 15/16 on cold days because we only have the input turned to 3 or 4 to save money. 
It has to be that the water cylinder is heating for the full five hours of off peak electricity. Is this normal to heat for the entire 5 hours? Would it really take this long? We don't have enough hot water anyway for 3 of us. It's a 145l tank and we run out after two very quick showers and no other hot water usage.
If anyone could advise me id be really grateful, even if it's just to reassure me this sounds about right!

QrizB

Welcome to the forum.

For a large property (how large, exactly?) 40kWh/day is pretty low. 60kWh/day is more typical and potentially 100kWh/day in the depths of winter.

For comparison my moderately-sized 3-bed semi is currently using around 40kWh/day, total, in both electricity and gas.

Your water tank will not be using 15kWh. Heating 145 litres of water from 5C (cold) to 65C (piping hot) will use 10kWh. After about three hours the thermostat in the heater will turn it off.

What supplier are you with and what tariff are you on? Do you know the rates?

Robin9

I would suggest that the Immersion Heater is up to temp in a couple of hours but do check that its the heater at the bottom of the tank that comes on at night.  Storage rads are the biggest consumer

Other night uses - fridge, freezer, lights

Day time use is amazingly low.

Do check the off peak times are 1230 to 730  -  may need to a bit of detective work to see when the meter clicks over. 

coffeehound

Hi @Aliceinwonderland1533.  Can you give the make and model of hot water tank please?

Gerry1

Your NSHs were probably charging up for much longer than three hours.  If they are the old style ones without a fan, turn down the output control when going to bed and turn it up if it gets too cool in the evening.

maisie_cat

Whatever heating system you have you will use a lot this time of year. When we moved in here 2 1/2 years ago the storage heaters were left on and we used 85 KWH in the first day.
We switched them off and relied on the oil Rayburn plus wood burner for 2 winters using around 88kwh/day for the winter months.
We now have central heating and we are currently using 78kwh/day between wood pellets, logs and electricity.

Swipe

As a comparison, I'm in a detached bungalow and I'm quite conservative with my storage heaters and use between 60-70kWh overnight in winter and 4-5kWh during the daytime.

markin

How long are the showers, time them, in mine 1 person can make a 100l tank cold in just 15min.

If its rented you need to move, if you cant afford it at 15p you will be freezing when the April cap comes in or your fixed deal ends.