Building Envelope Performance Targets
Summary
Envelope performance targets set measurable limits for heating demand and air leakage instead of prescribing insulation values. Passive House criteria are the common reference for high-performance targets and depend on airtight, thermal-bridge-free construction verified by testing.
Cols
Standards
- Heating demand: 15 kWh per square meter per year, or alternatively a peak heating load of 10 W per square meter (recommended, not mandatory)
- Airtightness: 0.6 ACH50, verified by an on-site pressure test in both pressurized and depressurized states
- Five principles: thermal-bridge-free design, superior windows, ventilation with heat recovery, quality insulation, and airtight construction
- Basis: the standard is performance-based and does not prescribe products or details
Coordination
- Verification: blower door test at completion
- Energy code: energy code envelope provisions are covered in the energy code notes in Codes, Zoning, and Standards
Sources
- Passive House Institute: Passive House requirements, https://passivehouse.com/02_informations/02_passive-house-requirements/02_passive-house-requirements.htm
- Building Science Corporation: the Passivhaus standard compared to other cold climate low-energy houses, https://www.buildingscience.com/documents/insights/bsi-025-the-passivhaus-passive-house-standard
- Wikimedia Commons: Rachel Dodgen, asset manager, documenting weaknesses in the building's thermal envelope (51221023601).jpg, by YellowstoneNPS (Public domain), https://commons.wikimedia.org/wiki/File:Rachel_Dodgen,_asset_manager,_documenting_weaknesses_in_the_building's_thermal_envelope_(51221023601).jpg