12" Open Air return, Ceiling Level in Basement

I have a 2600 sq” home and a major question. I hope someone can give me some advice.

The pertains to the intake plenums for the basement only. I have an air to air heat pump. And the plenums act like a regular hot air furnace.

There are two major cold air intake plenums for the basement. One is connected to a games room about 25 feet away and at floor level, while the other was just left a gaping hole on the top of the "furnace".

It appears to be an unfinished 2nd return for the Games room! There are two return registers in the games room at floor level and side by side?! With only one hooked up of course.

Now over 20 yrs later we are questioning why this was this left the way it was? Would two be needed in the basement from one room and side by side? The room is 13’6” X 30’.

There are no other cold air intakes in the basement including the garage that has 2 ceiling hot air vents, games room 3 hot air vents. One at the bottom of our basement stairs and one near the basement outside entrance.

We always felt drafting going down to the basement and the basement door would always slam behind shut by itself as would the two doors to the furnace room.

I decided to block the open intake that I believe was installed improperly/not finished and now have a reverse effect on the house pressure. Now all 3 doors to or in the basement are pressurized and need to be pushed shut. What do I do with this "spare" intake duct. Any help would be appreciated.

Thank - Alan

 

First, get rid of those two supply vents to the garage for your family's sake. Get some carbon monoxide detectors installed then when your oxygen levels return to normal you can think more clearly. Pipe the open hole to the empty space in the wall in your game room. Seal all the ducts that you can access.