Finished Basement - Return Air

Great forum. I am finishing my basement - is it recommended that I put in return air duct(s) for that space? Total basement is 1800 sq ft, there are 3 fresh air vents (installed by builder, new construction), so space is heated and air conditioned. So now, technically, air must rise upstairs to find a return air duct. Home is in Michigan. Floor plan is open with game room, media room, kitchennette, workshop and storage areas.
Thanks, Dan

 

Code requires at least one return duct on every floor. For 1800 square feet, you would be wise to consider more than one. Once you put up walls, you'll need more than the three supply vents too. The lucky thing is that there is no easier place to add ducts than an open basement with easy access to the main ducts.

 

Thanks, John.

So if code requires a return air on each floor, does that mean there should already be one installed by the builder? Or does that only apply to finished spaces?

Can I put an opening in the ceiling on an existing run?

Thanks, Dan

 

There won't be one already if the area is currently unfinished (as you already know by looking around).

You can tap into an existing run (using a "tee saddle"), but I would recommend against it for two reasons. The first of these is the more significant reason: (1) Noise -- the duct will be a major conduit for noise to travel between floors, and (2) You may compromise the air flow to the room above and/or have weak air flow to the room below.

It's not hard to add a new run. Buy a "take-off" and some 6" round pipe and a register box. Everything you need is in the HVAC aisle at Home Depot, and you can probably pick up a flier there too telling you how to install it.

 

You dont say how the layout of the basement is. Most of the time you want the cold air return down low in a basement. lots of times we put one in the cold air drop there by the furnace. make sure its on the intake side of the filter. Just get a 6"X14" grill and cut it in. Now you cant do this if you are going to close the furnace room up. You cant just cut in a takeoff and put a new run on a duct if it is not layed out for it from the start. ED