GCH vs Electric which is cheapest way to heat our water tank?

JethroUK

We have been heating our water tank via electric emmersion heater element 2 hours per night during economy 7
The element has blown
Shall bother fixing it or just put GCH on 2 hours in tye morning to heat the water tank up?
GCH vs Electric which is cheapest way to heat our water tank?

Smiley_Dan

The answer lies in how much water you are heating and how much you require.

Gas is always cheaper than electricity on a per kWh basis, but if you use less electricity because (for instance) the immersion coil is toward the top of the tank and therefore only the top of the tank is heated, less energy is required and so that may end up cheaper.

The input from the system boiler is likely to be much further down, heating the entire tank.

penrhyn

Gas is of course typically three times cheaper than electricity, however if you have an old decrepid boiler over half the heat is warming the atmosphere.

closed

depends how much you're paying per kwh during the night amongst other things

matelodave

Probably not a lot of difference.
Electricity is 100% efficient using an immersion heater so all the power consumed goes into the water.
A gas boiler can be anywhere between 70-90% efficient and will have to pump the water around the pipework which will incur heat losses, especially if they aren't insulated and the boiler is a long way from the tank. It's probably only about 50% efficient. You've also got to take into account the electricity required to power the boiler and pump.
Therefore it will take about 2kwh of gas into the boiler to heat the same amount of water as 1kwh of electricity into an immersion heater.
Depending on how much you pay for each will determine which is the cheapest.
Alternatively you could try reading the meters to see how much energy it takes to heat the tank

JethroUK

matelodave wrote: »

Probably not a lot of difference.
Electricity is 100% efficient ..... It's probably only about 50% efficient.

Actually dont give a monkeys about efficiency (input/output) and its totally irellevent to the question - and the only people that would think it rellevant dont actually understand "efficiency" at all
It is more "efficient" to walk to the moon than go in a rocket is about as much of an example as I can think off

Although gas being about 3rd the price of electricity is a better indicator thanks

closed

it's more efficient to use google

JethroUK

penrhyn wrote: »

Gas is of course typically three times cheaper than electricity, however if you have an old decrepid boiler over half the heat is warming the atmosphere.

Its not that old but the plumber quoted between £100 - £500 to repair and that buys a lot of gas even with the most rudimentary maths

JethroUK

closed wrote: »

it's more efficient to use google

Funny I grant you - but anyone who thinks thats actually true is an idiot 'by definition':)

ohreally

JethroUK wrote: »

Its not that old but the plumber quoted between £100 - £500 to repair and that buys a lot of gas even with the most rudimentary maths

My mothers immersion element failed, I replaced it for less than £25 and a couple of hours (drain the cylinder to below the element).

http://www.screwfix.com/p/immersion-heater-copper-element-11/89280?kpid=89280&cm_mmc=Google-_-Product%20Listing%20Ads-_-Sales%20Tracking-_-sales%20tracking%20url&gclid=CLOzu-GB6L4CFQYTwwod60IAcA

Pincher

On the other hand, I bought two titanium (so Plumbcenter claimed) immersion elements for a Gledhill Pulsacoil thermal store for about £150. Got the plumber to replace both elements. The 10+ year old elements were so stubborn, that the removal took so much twisting and banging, that the cylinder leaked, causing a minor flood down stairs, and eventual total replacement of the Pulsacoil thermal store, at a cost of £1,600.


So gas boiler gets my vote here.