Have a room addition 16x18' has 2 heating ducts and cold air return . Has 2 outside vents and a heating duct inside crawl space, floor is covered in concrete not smooth but no soil exposed. The crawl space has access to main basement through a basement window and crawl space is about 30" high. The rooms exterior walls were insulated when room was built. We added insulation in ceiling (attic) and insulation company insulated under the floor and wrapped the heating ducts and pipes and closed off the heating duct into crawl.... It is still cold in room and must use portable heaters in the winter. Should we open the basement window and insulated the exterior walls of crawl space and open the heating vent into crawl space and seal outside vents?..... If we do this should we remove the insulation under the floor or leave it. Also should more heating vents be added to the room? Confused and cold in northeast ohio.