Basement duct work

Bill Hetherington

I'm in the process of building a rec room in the basement. In the room there are two heat sources(registers) at the celing level. Is it better to leave them up or bring them down through the wall to be at floor level.

Brad White

It depends...

Always does.

Ideally, yes, the best place to bring warm air into a room for heating purposes is down low and if down low, along an outside wall. You want to create a barrier of warm air between you and the outside wall.

Correspondingly, the return air wants to be as remote as possible from the supply outlets. If they are down low then return high and away from them, ideally.

What depends is, are these branches closer to the fan than others? If they are far out away from the furnace, the ductwork will have less available pressure at that point. Also if the air is particularly hot (i.e.: not a condensing type furnace), you have the buoyancy to overcome.

If your basement heat loss is low, the concept of heating down low will not matter as much. Also if you drop them and they wind up on an inside wall blowing across to the exterior, you run the risk of blocking the outlets by furniture placement. It may be better to leave them up high but duct the outlets over near the outside wall and make sure the return is at least as remote as possible from the supplies.

How well does the space heat now? Only you can tell. If it suffers now your construction can mitigate this by insulation.

EDIT: One thought that occurred to me from a near-incident I recall a couple of years ago: Similar project, basement fit-out. The owner enclosed the furnace and louvered the door, that being the principle return air path. Fortunately the inspector caught that. The furnace was atmospheric and the fan negative pressure would have fought the chimney pulling combustion products back and throughout the house.

Don't do that. Be careful and thoughtful with your construction and install good CO detectors if you do not have them already.

Random drive-by thinking.

Brad

Jeff Lawrence_25

Good point

When I do a basement for a customer, I make doubly sure that the air flow is 'circular,' meaning the supply's (the blowing the air out) are at a different level than the returns.

Supplies in the ceiling, returns near the floor, etc.

Given the choice, I'd put HWBB in along all the exterior walls and gauge my water temp by the linear footage, if I could. maybe 120° maybe?