Wouldn't cost more as long as thermostat is not in same room as radiator full of air.
You would however notice a temperature drop in the room the radiator is sited in.
Water needs to travel to the top of the radiator and back down to the bottom with a given temperature loss to perform efficiently.
Jeff
You would however notice a temperature drop in the room the radiator is sited in.
Water needs to travel to the top of the radiator and back down to the bottom with a given temperature loss to perform efficiently.
Jeff