Do the phrases "This room is always too cold" or "My bathroom fan doesn't do anything" ring a bell? Whenever a homeowner complains about the performance of some heating or ventilating equipment, it's handy to have a flow-measuring device available to check out the complaint. The Research Division of Canada Mortgage and Housing Corporation (CMHC) has been testing ventilation system performance for years, sometimes with specially built equipment. While this equipment can accurately measure flows, it's too bulky, expensive, and fragile to be of real use in day-to-day inspections. So an inexpensive alternative was developed — the calibrated garbage bag. To make the bag tester, open a wire coat hanger up until you have a rough rectangle. Now tape the
