Have I done this right? On the new price cap rates
A 24kwh boiler will cost 24x0.15=£3.60 an hour for heating
A 35kwh boiler will cost 35x0.15=£5.25 per hour for heating
I'm not sure what our combi boiler is, but Google leads me to believe that in a 4 bed house it's probably a 35kwh boiler.
I've just ordered some heated throws!