Here in Canada Air/heat recovery exchangers are mandatory by code in all new construction, With tighter homes and less air infiltration would not larger volumes of air be nessesary rather than the downsizing of units as Ive read about?? P

The volume of air required for ventilation purposes is much smaller than that required to heat or cool via air movement.

If I remember correctly it's 0.3 air changes per hour in Ontario, so assuming a very tight house you'd want to figure out volume of house and make sure the HRV is sized for 0.3ACH. Victor www.ecobuilthome.ca A 4350sqft Net Zero Energy Initiative

Posted By peterswet on 22 Jan 2011 08:03 AM
Here in Canada Air/heat recovery exchangers are mandatory by code in all new construction, With tighter homes and less air infiltration would not larger volumes of air be nessesary rather than the downsizing of units as Ive read about?? P

peterswet - in Alberta heat recovery is not mandatory but mechanical ventilation is. If you are sizing an hrv remember to make it big enough that you will still get the required air exchange when you calculate the time the unit is in defrost or recirculating to clear the ice. Some units will be down for 20% of the time at minus 25. Check the unit.