Water heater - how long should they be on for?

Jmoo

So I've just received my bill for the quarter in my new flat and shockingly it appears to be £50-£75 per month in 1 bedroom flat. I'm not using a lot of electricity from what I can see, and I'm on Economy 7 for my storage heater. The only thing I can think that might cause problems is the water heater. How long should they be timed to come on for?

Here's the set-up: https://drive.google.com/file/d/0B_utf2lKoF2-ZGltMllkUDVOTDQ/view?usp=sharing

I often have a bath/shower in the morning, the occasional shower in the evening, and obviously do washing up and have a wash in the evening. At the moment it's meant to come on two and a half hours during Economy 7 time, and then for an hour or two in the evening. Is that too much? Will that be expensive?

Robin9

Energy is not cheap and £50- £75 for a winter month in an all electric flat isn't bad.

Cardew

Do you need to have the water heater on in the evening? - which will be at peak rates.

For the usage you describe, heating the water overnight at off-peak rates should suffice.

Even so £50 to £70 a month is not 'shocking'.

teddysmum

You could save money by boiling water in a kettle, when having a quick wash or doing just a few dishes, as there is no point in heating a whole tank of water, when only a little hot water will be needed.

Jmoo

Cardew wrote: »

Do you need to have the water heater on in the evening? - which will be at peak rates.

For the usage you describe, heating the water overnight at off-peak rates should suffice.

Even so £50 to £70 a month is not 'shocking'.

Hmm, it seemed a bit of a jump from £20/month in my last flat given I live on my own and I'm not usually there weekends. Everyone has different habits, for some £50 might be a bargain I guess.

teddysmum wrote: »

You could save money by boiling water in a kettle, when having a quick wash or doing just a few dishes, as there is no point in heating a whole tank of water, when only a little hot water will be needed.

That's a good point.

matelodave

Try turning it off for the evening - thats when you'll be paying for full rate electricity. There should be enough hot water for a whole day from an overnight heating cycle, unless you are profligate with it.

To save a bit of energy you could spend less time in the shower and have shallower baths. 10 minutes in a shower could use as much water as a bath. Try fitting aflow reducer to the shower to use less water.

Dont rinse or wash stuff with hot water if you can use cold and always put the plug in or use a bowl when washing yourself or the dishes.

Do you use additional heating as well as the storage heater - that will bump up your bill as well

Jmoo

I have occasionally used panel heaters, but not very often. Only in extreme instances.

Cardew

IMO there is far too much emphasis on this forum about how long the hot water should be left on; assuming you have a well insulated hot water tank.

A modern well insulated HW tank is tested to a British Standard and a typical test result is to have a heat loss of 1.5kWh over 24 hours with the water at 65C. On many tanks the loss figure is stamped on the tank(often in inaccessible places!)

As few people have their water temperature at 65C the 'real world' loss of a tank heated 24/7 at around 45C is probably around 1kWh a day. So carefully controlling how long the tank is heated for, will save a fraction of a kWh per day.

It is also relevant that any heat loss from the tank warms the fabric of the house; so isn't wasted for much of the year.

Jmoo

Thanks all. I can report my daytime usage over a 24 hour period has dropped to as little as 3kWh after stopping the daytime heating of hot water. This has increased the night time usage but given it will be cheaper hopefully that's a saving.