to ask if I'm right about energy costs per hour

[CleverClogg]

I keep trying to work out energy costs per hour for heating. I am ok with the cost of an electric radiator ( oil filled) 30p per kWh x 1kWh is obviously 30p. Its the gas I cant fathom. 7p per kWh x 24 kW boiler =£1.68 per hour? That seems humungous, and looking back at past bills it means we have had the heating on for less than 50 hours a month, at the height of winter - which seems hugely unlikely to me - I would say double that as a minimum, in the coldest months.

where am I going wrong?

YANBU - central heating with a condensing boiler in a 3 bed property really is £1.68 per hour

YABU - you are completely wrong and here is why....

Thank you!

The 24kw is the peak output, it's not running at that all the time. In fact, it'll be using less power and thefore cheaper the lower the temperature you run it at.

Similarly I have a 7kw heat pump, it's rarely running at full power.

24 kw is the full output of the boiler if it was running at full output for an hour. That would usually include constant hot water as well because gas boilers have a high output to cope with hot water demands. The heating demand is likely to be much lower 6-10kw. But this will vary depending on the outside temperature as well.
I think The easiest way is to read the meter put the heating on for 1 hour and don’t draw any hot water and then read the meter at the end of the hour. Now you need the house to be a reasonable temperature at the beginning of the hour and it’s not a good idea to do it on really cold day either.
To further complicate things the gas meter won’t necessarily give a reading in the same units you are charged in. A conversion calculation maybe required

Insulation and draught excluding is the way to reduce bills

great idea, thank you - I am doing that now

yep, this confirms my first calculation - that is costs less to run the central heating for an hour than it costs to run an oil filled electric heater for an hour ... 15p compared to 30 p - thank you for your suggestion

Also bear in mind that with the gas boiler you are heating the whole house, not just one room and if you have a thermostat and / or TRVs on your radiators, they will stop calling for heat when they get to temperature.
At this time of year, the central heating will run for short periods (mine is on for about 10 minutes) and this will get longer/ more frequent as it gets colder.

Glad you’ve got it sort