How much does gas central heating cost to run per hour?

scotsmantom

We have a modern four bedroomed detached house, well insulated, with a boiler and hot water tank, not combi, heating our water and 14 radiators. Roughly how much will it be costing to run for each hour it is on? We set the thermostat to 20 degrees and when weather gets colder will have it on for about 7 hours a day. Thanks.

QrizB

You've asked one of those "how long is a piece of string" questions. It's impossible to give a meaningful answer.

If you turned your central heating on back in July when the temperature outside was pushing 40C, it would probably have cost nothing to run. If you turn it on in the depths of January when it's -10C, it is likely to cost a lot more.

What exactly are you hoping to do with this bit of info?

[Deleted User]

It’s not that simple as this graph shows:

A modern 24kW boiler will modulate downwards as the house reaches temperature. When it reaches it lowest modulated output, it will start cycling off and on. How little gas you use will very much depend on how you run your boiler. To achieve maximum efficiency (lowest cost)the boiler flow temperature setting needs to be as low as possible and the return temperature needs to be below the dew point of 56C.  The lower the flow return temperature the better.

Another major factor is the outside temperature. The lower the outside temperature, the longer the boiler has to be on to maintain 20C - which in itself is a high inside temperature for most of the day.

Finally, turning down the temperatures in used rooms will save you money.

The vertical bars in the graph above show gas usage in kWh for each 30 minute period.

Astria

I remember last year when it was -4c outside, my gas cost approx £5/day, and was pretty much on 24/7, so about 20p/hour, but your cost could be completely different, and you can't say "I'll just have it on for 2 hours then and it'll cost 40p" because it depends on the temperature of the house at the moment it comes on to depend on how much work it has to do.

I did try to have it on just in the morning and night, but the difference was so small it was easier and more comfortable to just have it on 24/7.

scotsmantom

It seems this is indeed a complicated question. We have smart meters that were never activated so have no idea what anything costs to run except we read that tumble dryer, washing machine and dishwasher are the most electricity guzzling devices.
I guess we know our energy bill was £200 monthly in the hottest months of the year so any increase as we move into colder weather is the central heating as our fixed tariff and the energy price guarantee rates are almost the same.
Thanks.

macman

You might as well ask, 'how much will it cost to drive my car for an hour?' We don't know how many mpg, how fast you are driving, or what you pay for fuel.
The cost is easily determined by taking meter readings 24 hours apart (assuming no other gas appliances), converting the difference to kWh, and multiplying by your unit kWh rate for gas. But no point in doing that at this time of year, as the heating isn't on yet.
Alternatively, just divide your total annual gas spend, from your bills, by 365, and then by 24.

Astria

scotsmantom said:

It seems this is indeed a complicated question. We have smart meters that were never activated so have no idea what anything costs to run except we read that tumble dryer, washing machine and dishwasher are the most electricity guzzling devices.

My washing machine uses up 1.4kWh for a total 2 hour cycle, hardly a lot in the grand scheme of things.

Likewise, the drier uses up less than 2kWh typically.

But connect either to a smart meter for 10 minutes and you'll see it saying something like "Currently £1.00/hr" which although technically correct, is completely misleading. You could derive from that for example that the washing machine costs £2, which actually it's more like 42p.

Mstty

Best finger in the air is 16000 kWh a year in gas, let me know in a year how close I was👍

molerat

Back in the winter of 2010 when temperatures did not get above 0 for over a week and my heating was on 24/7 I used 12 metric units a day which equates to 135 kWh per day, average 5.5 kWh per hour.  Last year 14p per hour, this year 57p per hour - still less than a 2 kWh electric fire though.

bluenose1

I also am interested to know how much it costs to actually heat the house per hour using gas ch boiler. I have read that the average gas ch boiler uses  35 kw per hour so if the cost for gas is now 10.3p per kwh that would be  £3.61 per hour.
In the article below it discussed costs per hour, though it was before the latest price rises. 
 
https://boilerchoice.com/how-much-gas-does-a-boiler-use/

[Deleted User]

bluenose1 said:

I also am interested to know how much it costs to actually heat the house per hour using gas ch boiler. I have read that the average gas ch boiler uses  35 kw per hour so if the cost for gas is now 10.3p per kwh that would be  £3.61 per hour.
In the article below it discussed costs per hour, though it was before the latest price rises. 
 
https://boilerchoice.com/how-much-gas-does-a-boiler-use/

That's a terrible article.  Randomly switching between kW and kWh, getting wrong how efficiency works on a boiler, and I'm not even sure it gets the average size of boiler right.

I mean, it might have some useful information in the middle of the nonsense, but it's so confused I can't tell.