Cheapest way to heat water?

Mr_Toad

I have warm air heating in my home and tomorrow the engineer is coming to do the service.

As well as the warm air the boiler also contains a separate water heater with its own burner, pilot light etc..

It occurred to me today to ask on here if using the gas boiler for the hot water is cheaper than using an immersion heater, I have both but the immersion heater is off.

I live alone and use the hot water for pumped shower plus the usual hand washing etc. It used to be a no brainer, gas was cheaper than electric but I have no idea if that is still true.

CashStrapped

Just to clarify....

You have warm air for heating.

For hot water you have the choice of a gas boiler and or immersion.

You do not have radiators heated by the Gas boiler...


If the above is true, depending on the efficiency of your boiler (make/model) then the gas boiler will usually be cheapest to heat the water tank.

Gas costs around 2.5 - 3.5+ pence per KWH, Electric can cost 8-14+ pence per KWH

However....if the boiler is very old and less than 50% efficient, then the immersion heater could actually be cheaper. This is unlikely and can only be determined when you check your boiler age/make/model.

prosaver

i would bin the boilers and get an electric shower,
heat the water from the kettle for washing up..
or even better, buy a dishwasher with the money saved from not getting a new boiler,

Cardew

prosaver wrote: »

i would bin the boilers and get an electric shower,
heat the water from the kettle for washing up..
or even better, buy a dishwasher with the money saved from not getting a new boiler,

The OP has not said anything about getting a new boiler.


He/She merely wants to know if heating her hot water tank from the existing gas boiler is cheaper than heating that tank with an immersion heater, a question answered succinctly in post#2.


In any case why would you spend £hundreds getting an Electric shower fitted(cost of electric wiring alone can cost £hundreds) to get a much lower flow of electrically heated hot water costing three to four times as much as a shower heated by gas?

Swipe

prosaver wrote: »

i would bin the boilers

Then how will the OP heat their home?

Mr_Toad

CashStrapped wrote: »

Just to clarify....

You have warm air for heating.
Yes

For hot water you have the choice of a gas boiler and or immersion.
Yes
You do not have radiators heated by the Gas boiler...
Correct

If the above is true, depending on the efficiency of your boiler (make/model) then the gas boiler will usually be cheapest to heat the water tank.

Gas costs around 2.5 - 3.5+ pence per KWH, Electric can cost 8-14+ pence per KWH

However....if the boiler is very old and less than 50% efficient, then the immersion heater could actually be cheaper. This is unlikely and can only be determined when you check your boiler age/make/model.

Thank you, I just needed to check which was the cheaper. It was the impending boiler service made me wonder.

Boiler is efficient.

matelodave

I'm guessing that the "boiler" is what used to be known as a gas water circulator - looks a bit like an old Ascot (some might remember them). it heats the water and circulates it through the heating coils in the hot water tank. It does not heat the house.

A lot depends whether it's equipped with an electrically operated gas valve which would allow it to be both timer & thermostatically controlled.

We had one years ago and as far as I remember it just cooked away all day & night under the control of the return water temperature so wasn't all that controllable and consequently not very economical.

Probably the cheapest method of heating water is by use of an immersion heater on an E7 tariff, however that also assumes that you could optimise your use of low rate leccy and avoid using peak rate.

prosaver

Cardew wrote: »

The OP has not said anything about getting a new boiler.



He/She merely wants to know if heating her hot water tank from the existing gas boiler is cheaper than heating that tank with an immersion heater, a question answered succinctly in post#2.


In any case why would you spend £hundreds getting an Electric shower fitted(cost of electric wiring alone can cost £hundreds) to get a much lower flow of electrically heated hot water costing three to four times as much as a shower heated by gas?

if you didnt have a gas boiler you would save money on
no standing charge (cut gas off if they have a electric stove/ oven
no boiler insurance ..save 12-20 pounds a month.
no maintenance/repair save 80 pound a year at least
total save at least 260 a year.:beer::beer:
shower 90 from b and q
fitting it say 50 quid...- 260
do the maths ..too tired

matelodave

Read the OP's post - she's got gas fired warm air heating so she can't dispense with gas

r2015

I used to have warm air heating like yours and in the summer when the heating was off I used approx. 18 kWh of gas a day, including the pilot light.


That was for 2 or 3 showers a day plus cooking.


Now I use 12 kWh a day of gas for the same usage from my new combi boiler, a saving of 6 kWh a day but 3 kWh of that saving is the pilot light.


One advantage of the combi boiler is that if I don't use any hot water I don't use any gas, when I went on holiday and didn't turn the gas off I was using 5 kWh of gas a day just to keep the HWC hot.

Mr_Toad

matelodave wrote: »

I'm guessing that the "boiler" is what used to be known as a gas water circulator - looks a bit like an old Ascot (some might remember them). it heats the water and circulates it through the heating coils in the hot water tank. It does not heat the house.

A lot depends whether it's equipped with an electrically operated gas valve which would allow it to be both timer & thermostatically controlled.

We had one years ago and as far as I remember it just cooked away all day & night under the control of the return water temperature so wasn't all that controllable and consequently not very economical.

Probably the cheapest method of heating water is by use of an immersion heater on an E7 tariff, however that also assumes that you could optimise your use of low rate leccy and avoid using peak rate.

Not like an Ascot.

It's one of these, the Economair 65 Integan .
http://www.johnsonandstarley.co.uk/warm-air/economaire-range.asp#economaire-65

Just like a normal central heating boiler except that instead of pumping water round radiators it blows warm air round ducting and out of vents in the walls and floor downstairs and out of walls and ceiling vents upstairs.