Hello. I have two a bedroom at the NW and SW corners of my house that are quite a bit colder than the rest of the house in the winter. I measured the vent in my dining room and the temperature there was 95 degrees. I went to one of the bedrooms and the temperature was 82 degrees. This is a cement slab floored house with a half basement, and it doesn't really seem to me that the duct run to those two room would be more than maybe 30 feet. Does anyone know what may cause the 13 degree temperature difference?