Can you use flexible duct for Forced air?

Question

I'm assuming it's not as good , and will slow down air travelling through it, but it seems a little nicer for getting it by pipes that are there while I'm finishing my basement. Is there something better? Also for the return system, can you just leave an opening through the wall with a grate from the hallway to the furnace room? Does every room need a return duct for air?

Answer 1

Yes, you can use flexible duct for forced air. Usually pipe is better if you can use it. If space is a problem there is an oval pipe that works well. You can not just use a grate from the hallway to the furnace room, it must be attached to the return duct system. Every room does not need a return duct if you can get enough air flow out of the room by having space between the bottom of the door and the floor. It is better to have a return duct in every room, though.

Answer 2

yes flex is fine on forced air systems

Yes the opening should be ok for the return as long as the hallway has openings into the large rooms of the house

every room does not need a return duct in a house. the large rooms should lead off the hall. the bedrooms return air will find its way under doors and other places

Answer 3

its ok for short runs but if they are over 10 feet then go with metal heat pipe as far as you can then switch to flex-duct. you can have an open return but it will pick up smells from the furnace room you may not want circulating through your house. you need a return in each room if the door will be closed at any time

Answer 4

It'll work just fine . If the doors are going to be shut in a space then you need a cold air return otherwise maybe not keep in mind that all the air must pass through the a/c system to remove the humidity and thus cool the space.

Answer 5

The PVC they are refering to is the Chimney Pipe or the CPVC Exhaust pipe, not your internal ductwork. The condensate cannot be allowed to settle in the Chimney so they slope the pipe to help drain it, when they do this the water or condensate usually goes to a small sump pump as condensate, if you have central air conditioning that also creates condensate and the condensate would go to the same small sump pump. The condensate would be pumped out to the sewer or out on the ground both options are ok. Good Luck

Answer 6

yes but i wouldnt suggest going over six foot runs,a single 'wild' return is fine if your house is a ranch style and under 1100 sqft

Answer 7

We tried doing that in our new addition and it was a short distance...it didn't work!!