# Heating water from immersion or gas



## Conshine (28 Nov 2011)

I have gas that runs my central heating system and it also will heat the water if I set it to do so.
The upstairs and downstairs heating and water are on three separate timer settings for the boiler, so I can put them on at any time that suits.

But my plumber told me that I am better off using the immersion to heat the water rather than gas.
He said that the immersion heater uses electricity to heat the amount of water I need using the Sink setting.
If I was to use the gas, it uses electricity to run the boiler, plus gas to heat the water, plus it heats the whole tank.
What he says makes sense.

My question is, where I have the gas heating the radiators in the early morning, would it be better to use the boiler to heat the water at the same time as the heating is running, as it will then be doing the two jobs at the same time?
Then use the immersion at certain intervals for a top-up.
Or is it better to use the immersion always, regardless of when I have the heating running?


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## Leo (28 Nov 2011)

Your plumber doesn't really understand electricity if he's comparing the amount of electricity an immersion heating element uses to that your boiler uses. 

It will be considerably cheaper use the gas to heat your water, especially so as you're running it to heat the rads anyway.

Gas costs about one sixth that of electricity per [broken link removed]. 
Leo


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## STEINER (28 Nov 2011)

We never use the immersion, always the gas to heat the hot water tank.  Its no bother to have the water heating whenever the central heating is on, but even less than an hour water heating per day gives us economic hot water.  During the summer when we don't need central heating on the gas boiler heats our hot water tank only.  Our highest winter gas bill  would never exceed 140 euro and summer bills are about 40 euro per 2 months.  3 bed, 3 bathrooms.


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## Conshine (29 Nov 2011)

Thanks for your comments Leo!



Leo said:


> Your plumber doesn't really understand electricity if he's comparing the amount of electricity an immersion heating element uses to that your boiler uses.


Ok, maybe.



Leo said:


> It will be considerably cheaper use the gas to heat your water, especially so as you're running it to heat the rads anyway.


Ok, understood, and that makes sense



Leo said:


> Gas costs about one sixth that of electricity per [broken link removed].



This is really my query - I set the immersion on timer for 15 mins, which is one of the little notches on the timer and the switch on sink, then I have pretty hot water for hand washing and for the kitchen sink.

If I heat the water by the gas boiler, it takes an hour to heat the water to a similar temperature, plus it has heated the whole tank. It would make more sense to only heat what I need. If you are saying that the cost of running the boiler with electricity, plus the gas it burns for one hour is cheaper than running the immersion for 15 mins, then that is my question answered. I will use the gas and only immersion if the hot water is required quickly.


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## Shane007 (29 Nov 2011)

Conshine said:


> If I heat the water by the gas boiler, it takes an hour to heat the water to a similar temperature, plus it has heated the whole tank. It would make more sense to only heat what I need. If you are saying that the cost of running the boiler with electricity, plus the gas it burns for one hour is cheaper than running the immersion for 15 mins, then that is my question answered. I will use the gas and only immersion if the hot water is required quickly.


 
Is your cold water supply coming into the house high in limescale? This coul dbe a factor if the gas is taking a long time to heat the water as gas is normally very responsive for heating dhw.


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## sinky (12 Aug 2015)

Hello all I'm just wondering given current fuel prices of gas is still the more economical option? Thanks


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## Branz (12 Aug 2015)

sinky said:


> Hello all I'm just wondering given current fuel prices of gas is still the more economical option? Thanks


in a 4 year old thread, what has changed to ask the question.
elec is about 18cents kWh
gas is about 6 allowing for system inefficiencies


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