Roughly how much electricity is used if the gas central heating boiler is left on permanently?

I couldnt switch mine off because it also heats my mains water. That said i do have an eco button which i turn on to stop it turning on every couple of hours using gas and waking me through the night. 

Always wondering about this as even MSE experts seem to differ in opinion? Any hard evidence of reduced bills welcome please😂

I really struggle when the house is cold so always have our heat set to be on at a minimum 18 degrees during the day  We have a WiFi controlled heating system so can turn up when we get near home  we have ground the WiFi controller has saved us  loads we have had it over 10 years it is amazing.

We have our central heating turned off April to October inclusive.

We do however have a heat only not a combi boiler so that is on for 30 min each morning to heat 90 litres of water which supplies all  our daily needs. This costs less than 30p per day in gas and the pump during this time uses about 0.2 kwh of electricity.

Hope that helps

Hi
Very roughly 1 Watt continuous (standby) equates to around £3 per annum. Boiler standby is probably only a Watt or two so maybe £5 per annum?

In use say 20 Watts for the boiler, 20 Watts for the pump, running for an hour every day (0.040 kW * 30p ~ 1.2p per day ~ £4.40 per annum).

Each re-heat cycle of the tank must first heat the water circulating between boiler and tank. When the heat cycle completes this heat is lost to ambient. Pump over-run reduces these losses (residual water in the pipework is nearer to the tank temperature, rather than the boiler temperature) but this is still probably between 0.5 kWh and 1 kWh so minimise the number of re-heat cycles. Each cycle "wastes" around 3p of gas.

Judicious use of the timer to heat the water just before it is needed will help.

Since the boiler heats the whole tank to a similar temperature (the top may be just a few degrees hotter than the bottom), but when you use hot water, cold water enters the bottom of the tank and "pushes" the hot water up, you can make savings by moving the tank hot water thermostat from the bottom of the tank to about mid-way up. Usual warning about only  qualified people should work on electrics....

If you have a top mounted immersion heater and use little hot water during the day consider using a timer to turn the immersion on for say 15 to 30 minutes during the off-peak period and then using the boiler prior to major hot water demands (e.g. bath in the evening). Although off-peak electricity is around 3 times dearer than gas, if you only need enough hot water in the morning for a shower, wash or some washing up then this may be cheaper. You might get away with just 1 kWh of electricity, versus say 4 kWh of gas to heat the whole tank. 

Hope this helps

BP

@Nukecad thanks for your very informative response. I have a combi boiler that heats water direct too so BeePee's (also very informative) response didn't apply. I was only curious because a friend was adamant that switching off was more costly. 

My heating is currently turned off at my room thermostat and I hope it will remain so until well into November! 

I would just add for anyone reading this thread, just be careful and don't get cold regularly if you have conditions like high blood pressure. 

For example my blood pressure is pretty high although reasonably well controlled. 

We are careful these days not to let the temperature drop. 

https://www.bhf.org.uk/informationsupport/support/practical-support/will-cold-weather-affect-my-heart-condition

Always a balancing act with the cost these days for many people of course. 

You friend would be correct if you had a water tank rather than a combi boiler.

In that case switching off the gas boiler would mean that you were heating the tank using the electric heater in the tank, electricity instead of gas.
And of course electricity costs much more per kWh than gas does so it would cost more to heat the same amount of water.

I live up North on the coast of Cumbria, my room stat is set at 19.5 degrees and it’s been firing up for the last few weeks now. Winter is coming.

@Nukecad 

I guess living in the southwest has its advantages! My living room has a huge south facing floor to ceiling window. Even in winter if the sun is shining I can turn the room thermostat off for a few hours over midday. 

I had the good fortune to start a 2 year fixed rate contract just before energy prices soared in 2021 - but the renewal prices (I chose variable for now) have been quite a shock.

Joining Power Move was a no brainer for me - as a pensioner and living alone it's not a problem to schedule my main electricity usage outside of 4-7 pm.

Sorry, gone a bit off topic! 

It's a no brainer for those of us who cook with electricity. Just change when you cook and you shoud meet target. (I've been checking mine daily and have been below 6% every day this week simply by changing when I cook).

But, as some forum posts show, if you cook with gas then it's almost impossible to meet the target without actually increasing usage elsewhere. Eg start cooking with electricity outside of 4-7. With gas cooking there is just no big electricity use to “move”.

AS you know Combi boilers heat water on-demand rather than storing water for the day in the hot water tank (although some combis do have a small buffer tank). The advice to turn down your boiler thermostat is best applicable to Combi boilers for a couple of reasons.

1) The boiler enters condensing mode below 60°C, increasing its efficiency. There is some debate as to whether Combi boilers still need to heat water to 60°C to remove Legionella since the water isn't stored it just passes through quickly flushing the bacteria out of the system, a bit like an electric shower.

2) Whenever you use hot water, the water from the boiler/tank must reach the tap before it gets hot. When you turn the tap off the water left in the pipework is left to cool down. The hotter the water, the more heat is wasted. We do the washing up three times a day. The "trapped" volume is about 2 litres. With a water temperature of 70°C this waste around £10 p.a., at 50°C this falls to around £6.50.

For those with a Heat Only system and a water tank, turning down the boiler thermostat has problems. If the boiler is set to 60°C then there is no way the hot water tank can reach the same temperature (there must be a temperature difference between the boiler and tank for the tank to heat). Boilers use a certain temperature hysteresis to ensure that the boiler isn't constantly switching on and off. This is probably 10°C or more. So if the boiler flow temperature exceed 60°C it will switch off and wait until the flow temperature falls below say 50°C. Hence when the tank reaches 50°C the pump will run continuously, whilst the boiler remains off, wasting electricity.