I live in Philadelphia and live in a house over 150 years old. The house is 3 full floors with a dormer Attic that we are remodeling as the fourth floor. The space is about 15 by 22. There is currently no heat in there. We plan to make it a bedroom area. We have hot water radiators and a brand new Weil-McClain boiler CGa 140,000 btus. The sq. ft. of the bottom three floors is about 2500. We are trying to decide whether to run pipe to the fourth floor from our existing system and add a radiator or do something different. We have window units in the house for AC. A contractor recommended a Mitsubishi MSZ unit for heating and cooling. Another option is just an electric oil radiator.

Suggestions?