Whole-House Fresh Air Supply
A whole-house mechanical fresh-air supply system is provided.
Spec
Applies uniformly from Silver upward.
Scope
Continuous or intermittent mechanical ventilation that supplies outdoor air to the dwelling — separate from spot ventilation (bath fans, kitchen hood).
Requirements
- 01.
Install a whole-house ventilation system meeting ASHRAE 62.2-2022 airflow minimums (typically 30-90 CFM for a 1500-3000 sf home, depending on bedrooms).
- 02.
Acceptable system types: dedicated supply fan, exhaust-only with passive inlets, or balanced (supply + exhaust with optional heat recovery — required at Gold).
- 03.
Run-time controls must ensure the design CFM is delivered as an average over each 4-hour period.
Documentation
Evidence the inspector / Institute will need.
- 01.
ASHRAE 62.2 ventilation calculation worksheet showing required CFM for the dwelling.
- 02.
Ventilation system spec sheet + photo of installed fan / controls.
- 03.
Flow test confirming delivered CFM at the grille(s).
Guidance
Why tight houses need this
Modern construction is tight enough that natural infiltration alone no longer dilutes indoor pollutants to safe levels — VOCs from finishes, CO2 from occupants, moisture from cooking/showering, and (for the unlucky) radon all accumulate. The whole-house fan is the air-quality equivalent of a circulating pump in a plumbing system.
Resources
- ASHRAE 62.2-2022
The governing standard for residential ventilation. Most modern energy codes reference it.
- Building Science Corporation — Designing for Ventilation →
Practical guide to ventilation system selection.
Change history
Propose a change →History unavailable right now — see this requirement's full history on GitHub.
This requirement is open source — its complete edit history is public, and changes become certifiable when the Institute ratifies them into a release. See the standard-wide changelog.