Hmm. Outside air is required to feed the furnace. I understand that. However, does the requirement for ducting outside air into the space around the furnace change when there is also a heat recovery ventilator (HRV) in the house? The HRV brings the fresh air into the house from outdoors, but warms, or tempers it before ducting into the supply side of the furnace?
This seems intelligent, whereas bringing cold air into the house and simply dumping it (untempered) into the basement seems counter productive especially at -20C! Would the continued use for this be simply for the domestic water heater?
My suburban house is only 15 years old, but since tract housing is done on the cheap, it doesn't surprise me much.