I have a newer split level house (2006) with unfinished basement. The natural gas furnace is on the lower level in a utility room that is also laundry and bathroom. There's an enormous 8 or 10" pipe that serves as combustion air intake just over the furnace, which goes outdoors through a screened hole.
Now that it's become very cold outside (0°F/-17°C tonight) the intake seems to just be cooling off the entire lower level.
The furnace is not in its own enclosed space; it's open to the unfinished laundry/bath room, and the door to the room has a gap of about 1" to the concrete floor. If I stand just in front of the furnace, which is the same location to do laundry (just the opposite direction), the cold draft is noticeable even when the furnace isn't running.
Do I need to enclose the furnace in its own space to avoid this problem, or something else? I understand its purpose, but it seems to counter efficiency.