The Passive House must meet the air-sealing requirement of .6ACH50. This will ensure that drafts be kept out of the building, heating loads are significantly reduced, and that moisture is kept out of the building envelope.
Passive House, .6ACH50, air-leakage requirement, building envelope, air-sealing, reduced heating loads, reduced drafts, better bulding durability, moisture management
Passive House is standard for energy-efficiency that results in ultra-low energy use, very comfortable and healthful buildings.
Three requirements must be met in order for a building to be a Passive House:
1. Air leakage of the building must be at or below .6ACF50.
2. Space heating and cooling demands less than 4.75kBTU/SF/year OR the peak heating load must be is less than 3.17BTU/hour/SF.
3. Primary energy use must be less than 38.1kBTU/SF/year.
Keeping air leakage below .6ACF50 will keep drafts out of the building and reduce the heating loads. If the air leakage were anything higher than negligible (.6ACF50), the Passive House heating demand requirement would be very difficult to meet.
Although the Passive House standard primarily addresses energy use, moisture management—keeping water out of the building and building durability—keeping mold and rot out of the building, is of paramount importance. The air leakage requirement is the first line of defense in moisture management and maintaining building durability and may well be the most important of all of the requirements.