How much does a gas combi boiler cost to run?

[jsmoke]

At a quick look at the manual, my combi boiler is rated at 9-24KW. I assume this means if at lowest setting it's 9KW and at higest setting 24KW. I could be wrong though, maybe it was referring to different models, it wasn't very clear

So it's 4p per KW of gas, but as I said a boiler will use up to 24KW on full settings. So, does a combi boiler heat a full tank of water even if just one radiator is switched on and how much would this cost per hour, any experst here?

It can't be say 20KW * 4p + standing charge that would work out at £1.10 per hour, mayne that's right though.

 

[dark-knight]

"So, does a combi boiler heat a full tank of water even if just one radiator is switched on"

No, a combi boiler will only heat up the required amount of water that is required at that time. If you turn a hot water tap on the initial water should be cold/warm and will increase in temperature as the boiler fires up to heat the water required. The radiators are on a separate system so to speak, the temperature is governed by the house thermostat or that installed on the radiator so no hot water (for use) should be produced unless being used.

Unsure about the cost, I run it when needed and let the energy provider deal with the rest.

 

[gort]

For your actual boiler you could crank up the thermostat and let the boiler run on full for an hour or two, taking the gas meter reading before and directly after you turn it off and calculate from there.
Should give you a reasonably accurate cost per hour at max output I'd have thought.