Electric immersion or boiler?

[Orlando]

Does anyone know if its cheaper to put the electric immersion on for an hour for hot water than putting the boiler on for hot water?

 

[Diyisfun]

immersion only heats the water 100% efficient, boiler is probably about 50%, but then is the calculation of gas v electric.
At guess electricity would more efficient but not as cheap.

 

[Steve]

the way to tell is to do two experiments on two seperate days. Very impt. to do it on different days because the water must cool completely in between for it to be fair. Also very important is that there must be no other appliances in use, or pilot lights burning. Switch off any other boilers, and switch off ALL other appliances (easiest to just leave the immersion MCB on in the consumer unit).

From cold, turn on the boiler's cylinder heating circuit until the cylinder stat cuts out (about 60 degrees). Look at the gas meter and see how much gas has been consumed. Look at your bill (the gas calculations on it) and work out how much this has cost you to heat the water to 60 degrees.

Next day, turn on the immersion by itself and wait for it to cut out at 60 degrees. This calculation is easier than the gas one - the electric meter reads in KWH - multiply the KWH used by the pence per KWH on your bill.

Its no good to put them on for an hour. both appliances have KWH ratings on them - you can work out how much they will cost in an hour without even switching them on. To work out how efficient they are, you need to run them to cut-out temperature.

 

[Adam_151]

If you use very little gas and it happens to be 3 am and your are on a tarriff that gives you cheap night rate, then electricity might just be a tad cheaper (not by much though) Normally though, gas will be by far the cheaper option (and its more efficent as well, a gas boiler is somewhere around 80% efficent, a power station is 33% efficent...)

 

[Diyisfun]

Adam_151
(not by much though) Normally though, gas will be by far the cheaper option (and its more efficent as well, a gas boiler is somewhere around 80% efficent, a power station is 33% efficent...)

I dont think we should be talking about efficiency to generate...THAT is totaly different

 

[Kes]

Hi,

I don't think we've established what powers the boiler yet.

Rgds.

 

[plugwash]

not really, the cost and environmental impact of both will largely be tied to thier total fuel usage (though off peak leccy has the advantage that its usually generated from cheaper coal and nuclear), which will be tied to the full system efficiancy. Whether the losses are on the suppliers side or the customers side doesn't really matter in the grand scheme of things.