emersion heater costs?

benjacksmum

I was just wondering if anybody knows in general as to whether it is cheaper to leave the emersion heater on 24 hours a day, or to switch it on when we need sufficient water for a bath etc? Not only would this help with our electricity bill but also settle a 2year+ argument!! Thank you

chuckles1066

benjacksmum wrote: »

I was just wondering if anybody knows in general as to whether it is cheaper to leave the emersion heater on 24 hours a day, or to switch it on when we need sufficient water for a bath etc? Not only would this help with our electricity bill but also settle a 2year+ argument!! Thank you

Immersion heaters are phenomenally expensive.

You wouldn't want to be running one 24/7.

jojo20_2

someone told me that it was more economical to leave on as long as you have a thermostat
ihave done this for about 8 weeks but now i am getting a bit worried

Cardew

chuckles1066 wrote: »

Immersion heaters are phenomenally expensive.

You wouldn't want to be running one 24/7.

That really isn't accurate; or at least needs clarification.

The normal immersion heater is 3kW(some are 2kW) so it costs 3 times the the rate you pay for electricity(8p to 10p on most daytime rates) so 24p to 30p an hour - when it is heating.

However as mentioned above all immersion heaters are thermostatically controlled - otherwise the tank would literally boil.

Depending on the size of your tank it would take between 30mins and an hour to heat a cold tank to, say, 65C.

A well insulated tank will lose surprisingly little heat if no hot water is drawn off and, as it cools, the rate at which it loses heat slows.

However if you have it switched on 24/7 as you draw off water the tank is topped up with cold water and the heater starts heating again, so you always have a full tank of hot water.

Now you don't need a full tank of hot water, say, during the night or when you are out at work.

So the most economical method is to have the immersion heater timer to come on to provide sufficient hot water for your needs just before you, say, get up in the morning. It should not be on while you are drawing off hot water. e.g. if you get up at 7am your immersion should be on and switch off before 7am.

You have to experiment to get timings to suit your pattern of use.

Obviously if you are on economy 7 you have it on during the 7 hour cheap rate time.

That said, with a well lagged tank, even having it on 24/7 will not make a huge difference in your bills. More expensive - but not a disaster.