[abogart]

My idea is to simply run a damped fresh air duct from outside to the furnace intake, and a dedicated one-way vent to allow air from the living space into the basement to supply make-up air for furnace and DHW combustion and the clothes dryer. That way, when the furnace is running, the combustion blower is pulling a set amount of air out of the basement, which pulls stale air from the house into the basement, and the difference in static pressure (between inside and outside the house) pulls fresh air into the furnace intake to be heated and sent to the living space.

This is obviously not a very efficient design, since there is no actual heat exchange going on, but it's better than opening windows on a cold day. Since the furnace is going to send a set amount of air out of the house anyway for combustion, better to have it come in from one spot and get heated directly than to have it seep in through cracks in windows and doors. I suppose a HE could be added eventually between the fresh outside air and the stale air entering the basement. That could make for a cold basement, but the difference would be less energy consumed to heat the supply air to the house.