My house is 2 years old. My master bedroom sitting area is over the garage and that section of the room is considerably cooler than the rest of the room. I also have kneewalls(clipped ceilings)with attic space accessible through the garage in that area as well. Is there anything I can do about this? I am guessing the cold air is coming through the floor between the garage and bedroom. The garage ceiling is insulated with fiberglass, not foam. I was wondering if foam insulation might help, but not sure how much that would cost in a 2 car garage.
My next issue is I have cold air coming in through a return air vent on 3rd floor (attic space behind vent) and it moves down the stairs to the 2nd floor and into my daughters bedroom. I also have cold air coming in through an air supply vent in my master bedroom sitting area. This vent is in one of the kneewalls. Is this normal?
Lastly I have a forced air zoned (1 for each of the three floors in my home) furnace system. Regardless of which furnace turns on at least for the 1st and 2nd floors there is a whistling sound the entire time it is on, but once the thermostat clicks to turn it off (there's a few seconds before it actually goes off) the noise stops. Could this be ductwork, gas pressure issue. I can hear the whistling noise perhaps in several of the walls but it may be an echo going on throughout the ductwork. Any ideas?
Also I have read about negative pressure in rooms without return air vents and to open doors to help the room heat better. What is this all about?