We do not use the large front room in Winter. I shut the vents where the hot air comes out. There is an air intake too. Should I block it off too? A thick curtain divides the room from the rest of the house. Please advise.
Thought it is not absolutely required you may want to. This room will become colder than the rest of the house and drawing air from this room will thus make your furnace work a little harder to circulate the warm air to the rest of the house. It is kind of like adding hot and warm air to a bath tub the more cold water you have in the tub the more hot water you have to add to get it to the temperature you want. Be careful you don't let that room get to cold. Constant large shifts in temperature over the course of many years can cause walls to crack though this is far far more common with plaster walls than dry-wall (Which is found in most modern homes).