4.5 Million and they jam my HRV between two roof rafters and so I can’t open it to clean the filters?? It’s also so undersized it won’t move any air in my home. Here’s just another brand new home in the District of North Vancouver with an undersized HRV that was made for a small condo. When sizing an HRV in British Columbia the building code has a minimum requirement for the air exchange in the home. The sq/ft of the home X the average ceiling height X 1 (if there is no air conditioning) or .5 (if there is A/C) = the cubic volume or air required to be exchanged / 60mins = the minimum CFM required by the B.C. Building Code 9.32.2.1 Required Ventilation.

If the equation is so simply why do I continue to find these undersized?