Hello Rob. I am guessing that the heater will have to = loss in watts per square meter and then some, sounds like an insulation job first, in my experience there is little difference in electric heater efficiency, watts = power = heat and all that heat is released into the space unless it is directly sinked to the floor or wall, nightstore might be cheaper to run possibly. There is always my favourite...a wood burner or do what my dad used to do, stick old newspapers up the trouser legs then tie off trouser bottoms with some baler twine, he used to do that in the house!
Lawrence.
Lawrence.
