How do you determine the correct sizing of an HRV?
According to the Home Ventilating Institute a home should provide 0.35 ACH which is approximately 50CFM per 1000 sq ft (this recommendation is based on ASHRAE 62.2) but it doesnt say if this is additional ventilation to natural ventilation or not. is 0.35 ACH independent of the current air tightness of a home or is it assuming a home of 0 ACH? It's not clear. I ask because I am concerned my HRV is undersized. I have 3300 sq ft of living space, an air tightness of 1.5ACH and an HRV with 59CFM. Hope someone can clarify. Cheers
To properly size a home ventilation system you really should have a professional, and you may need one anyway for permitting. We don't like to weigh in on topics that where you will need a professional to sign off on a design as building code requirements often vary significantly by region. You can find HVAC contractors and designers here in our Building Professionals Directory -
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How to choose between an HRV and ERV home ventilation system: which is best?