I'm buying a new construction home with an unfinshed basement. The house has a high efficiency forced air furnace and central air. The basement is rough framed for two bedrooms, a large family room, bathroom, laundry room, and furnace/utility room. The home is a split foyer with a wide and open stair case going up to a vaulted ceiling foyer. The landing area in the basement has a large cold air return vent mounted near floor height. The finished space will be about 1150 sq. ft.
None of the basement has been ducted for heat/air registers. The house has truss floor joists and all of the upstairs ducting runs through those. I plan to drywall the ceilings of the basement.
My question is, can I tap into the main trunk in the ceiling and run short ducts to downward pointing registers in the basement ceiling? Or is it better, (or even possible) to run flexible ducting from the main trunks down through the 2x4 walls to registers placed near the bottom of the walls in each room? I figure that I only need one register in each room, with the exception of the furnace room.
A frined of mine ran his through the ceiling joists and mounted the registers in the ceiling pointing down. Looked much easier, but not sure about the efficiency.
Run a new main trunk for just the basement, then you can add a zoning system either now, or later.
When the basement and main level are on the same trunk lines. The coldest air from the main level falls and cools the basement. And since the thermostat is on the main level, the heat doesn't run until the main level cools off, and by that time the basement is several degrees cooler.