Gas water heating versus electric immersion

[Deleted User]

It sounds (on the TV) as though gas is going up much more than electric. I'm wondering whether to not use the gas to heat my water twice a day, but bung on the immersion instead.
Question 2... If I bung on the immersion instead, will it be cheaper to switch on twice a day for an hour, or to leave it on all the time?
Any advice welcome.
Lesley

Cardew

Covered lots of times.

Gas costs approx 3p for a kWh. The efficiency of your boiler can be anything from 50% for a really ancient boiler, to 95% for a modern model.

So the cost will be between 3p to 6p for a kWh.

Electricity costs approx 10p for a kWh.*

So gas will always be cheaper.

*Inevitably someone will suggest getting Economy 7 electricity at 4p to 5p, but then you pay extra for all of the rst of your electricity.

So GAS

[Deleted User]

Cardew wrote: »

Covered lots of times.

Gas costs approx 3p for a kWh. The efficiency of your boiler can be anything from 50% for a really ancient boiler, to 95% for a modern model.

So the cost will be between 3p to 6p for a kWh.

Electricity costs approx 10p for a kWh.*

So gas will always be cheaper.

*Inevitably someone will suggest getting Economy 7 electricity at 4p to 5p, but then you pay extra for all of the rst of your electricity.

So GAS

I'm sorry that its been covered before. Thanks for the advice though.
Lesley

Cardew

Mentioning that it has been covered before was not a rebuke, but merely to point out that the answer I gave is confirmed by plenty of people.

magician1

I've read your reply, what about if you use an indirect source such as a back boiler were the imersion is a good way away ? you have to run a pump and heat all that water and whats the efficiency of the heat excanger in the tank ? surely these would be a factor and make the use of cheap economy 7 a must if you use it to run dishwashers and tumble driers etc ?

bryanb

I don't mean top hijack the thread, but I've been thinking on similar lines recently. Normally we heat a 30 gallon tank of water for an hour each morning when the central heating comes on. In this weather the CH is off, so we are heating a lot of water to wash up twice a day. (We have an electric shower)
Any thoughts on whether it would be more economic to turn off the boiler and boil a ketttle to wash up?

Cardew

bryanb wrote: »

I don't mean top hijack the thread, but I've been thinking on similar lines recently. Normally we heat a 30 gallon tank of water for an hour each morning when the central heating comes on. In this weather the CH is off, so we are heating a lot of water to wash up twice a day. (We have an electric shower)
Any thoughts on whether it would be more economic to turn off the boiler and boil a ketttle to wash up?

What matters is the amount of heat your HW tank will lose.

A modern well lagged tank will lose about 2 to 3 kWh in 24 hours, so you are not heating up a whole tank but replacing the heat lost and of course the hot water you use.

Depending on the efficiency of your gas boiler that lost heat will cost in the region of 10p a day.

The heating of a kettle will use very little electricity(but still more expensive than gas) so there is little doubt that you will save something by shutting off CH - but is it worth it?????

bryanb

Cardew wrote: »

What matters is the amount of heat your HW tank will lose.

A modern well lagged tank will lose about 2 to 3 kWh in 24 hours, so you are not heating up a whole tank but replacing the heat lost and of course the hot water you use.

Depending on the efficiency of your gas boiler that lost heat will cost in the region of 10p a day.

The heating of a kettle will use very little electricity(but still more expensive than gas) so there is little doubt that you will save something by shutting off CH - but is it worth it?????

Thanks, would you say a copper tank with about 25mm of foam insulation (at manufacture) is modern, well lagged? Should I add more insulation, access is limited at one side and rear of tank.

ronald208

If you can put more insulation on the tank do it. It made a noticable difference to my gas consumption when I put an extra jacket round my already foam insulated tank.

It only cost me £10 from Wickes.

Ronald

gord115

bryanb wrote: »

I don't mean top hijack the thread, but I've been thinking on similar lines recently. Normally we heat a 30 gallon tank of water for an hour each morning when the central heating comes on. In this weather the CH is off, so we are heating a lot of water to wash up twice a day. (We have an electric shower)
Any thoughts on whether it would be more economic to turn off the boiler and boil a kettle to wash up?

I'd have thought using the kettle. If the kettle is only on for a few minutes at a time and uses say 0.15kwh or probably less each time,it will use far less the an immersion heater which is usually 3kw and you are using for 120 minutes a day(6kwh).

Cardew

Originally Posted by bryanb
I don't mean top hijack the thread, but I've been thinking on similar lines recently. Normally we heat a 30 gallon tank of water for an hour each morning when the central heating comes on. In this weather the CH is off, so we are heating a lot of water to wash up twice a day. (We have an electric shower)
Any thoughts on whether it would be more economic to turn off the boiler and boil a kettle to wash up?

gord115 wrote: »

I'd have thought using the kettle. If the kettle is only on for a few minutes at a time and uses say 0.15kwh or probably less each time,it will use far less the an immersion heater which is usually 3kw and you are using for 120 minutes a day(6kwh).

Where does it say he would be heating the tank with an immersion heater?

Even if it were an immersion heater, if it is on for 2 hours(he said 1 hour) it doesn't mean that it will use 6kWh as they are thermostatically controlled.