My mother, in Minnesota, has a Carrier Weathermaker 8000. The installer ran a fresh air intake from the outside of the house and down along the side of the furnace, to about 12" above the floor. It spills cold air into the house even when the furnace isn't operating.

Should this have been brought directly into the furnace? Any suggestions on how it can be set up so that air only enters when the furnace operates?

Thanks.

Where is the furnace in the house ? Is it in a closet or garage?

It's in the basement, half of which is finished living space.

Then it is in an open space and the combustion air is allowed to enter the entire basement area, since this is an 80% AFUE furnace you have to have the combustion air, the furnace has an open burner so it would not help to take it into the furnace. The 90% AFUE furnaces bring in the combustion air through a PVC piped directly to the furnace and these have a sealed combustion burner.
What might be an option would be to build a closet around the furnace and contain the outside air to this closet, Hope this is helpful, Mike

Thanks, Mike. Enclosing it may be the way to go.