Its currently 12 degrees outside and I live in a new home and burn propane to heat with a forced air furnace and airconditioner. A couple of our rooms (bedrooms) are noticably cooler than the rest of the home and we have been talking with people and the contractor on how to fix the issue. One topic brought up was to stuff towels to plug the fresh air intake for the furnace and eliminate the cold air entering the house that way.

What are the impacts and risks involved in plugging the fresh air intake and is it a good alternative?

Thanks for your help-