Cold Air Return In Attic

If the supply ducts are high or in the ceiling then the return air ducts or grills should be low on a wall.

Cold air return in attic. The return air vent openings need to be on the opposite side of the room so the conditioned air is pulled across the room. That would then reduce the flow of conditioned air to that space. It is very difficult to make such cavity spaces airtight. First building codes in many areas require that the cold air return line gets external insulation and therefore you will need to leave a gap for the insulation around the duct return line.

I live in a 3 story townhouse and my return air ducts for the 3rd floor run through the attic space. Unlike supply vents return vents do not need to be cased in metal. The return vent pulls cold air from the bottom of the room and returns it to the furnace to be reheated and returned as warm air. Cavities or interstitial spaces within walls are also sometimes used as supply or return air pathways.

These cavities often create a connection of inside air with outside air from an attic or crawlspace. If you had no return air in your room you would create a positive pressure. This pulls the air across your body. A cold air return is a vent that sucks cold air into a furnace so that it can be heated and brought back to a room through a furnace register.

These vents are seen in many types of furnace systems although there are alternatives such as drawing air from the outside or from the area around the furnace. Instead of bringing in air from the home it creates a negative pressure environment where clean conditioned air is replaced by unfiltered outdoor air. If the supply ducts are in the floor then the return air should be located up high. Running a metal cold air return duct between studs requires knowledge of both hvac systems and the components involved in framing.

In other words there s a lot of air infiltration. For the system to work you have to re circulate the air back to the furnace. That is why you need a cold air return image 1. When bedroom doors are closed the return is starved for air.

Place your cold air return vents on the inside walls of buildings at the lowest point.