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Design the air barrier and set an airtightness target

Air leaks can cause 15 to 25 percent of winter heat loss (Your Home). An airtight house needs a planned, continuous air barrier and a planned fresh-air supply.

How

1. Pick one layer as the air barrier (taped sheathing, membrane, plaster or SIP skins) and trace it around every wall, roof and floor junction on the drawings.
2. Detail tape and seal points at windows, doors, service penetrations and the wall to roof junction. DOE lists at least 19 key leak areas.
3. Set a measured target with your designer. For reference, the Passive House standard limits leakage to 0.6 air changes per hour at 50 Pa (ACH50); some codes set looser climate-based limits.
4. Design controlled ventilation (for example heat recovery ventilation) with the thermal module; DOE warns tight homes need planned ventilation to avoid moisture and combustion gas build-up.
5. Plan a mid-build blower door test before linings close (design-21).

Safety: Any wood stove or combustion appliance in a tight house needs its own outside air and a professionally checked flue (thermal and safety modules).

Sources

1. Passive heating. Your Home, Australian Government, accessed 2026-11
2. Consumer Guide to Air Sealing the Home (DOE/EE-2470). US Department of Energy, Energy Saver, accessed 2026-11
3. Passive House standard method (BASIX thermal performance). NSW Government Planning Portal, Australia, accessed 2026-11
4. Passive design. Your Home, Australian Government, accessed 2026-11

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