source of heat for basement rooms
I have a single vent to two built out half-basement rooms which seems to be inadequate to heat the spaces. I am working on trying to address whether or not I have sufficient insulation, but would like advice on adding another heat source to this area. There is a very cold bathroom where the foundation forms one bathroom wall. It has a ceiling fan heater that is quite noisy and not pleasant to use. The room is very cold in the winter. The other two rooms vary in temperature depending on how close you are to the high wall vent.
Would it be worth looking into adding an electric towel warmer to the bathroom and another heat source to the baseboards or walls of the basement rooms? I'm trying to be energy efficient. We can use an portable electric fan heater but it is expensive and noisy.
It is amazing to me that the adjacent garage with its large door vents is usually warmer than the interior, probably from the water heater keeping the garage warm. We do have insulation, both floor and walls, but apparently it isn't adequate.
Any ideas regarding an efficient system? We have an efficient gas furnace in the attic two stories above the basement and have a Solar PV for electric use. There is a small closet where we can add a small water heater for radiant heat if needed but I dont know if that makes much sense.