Air Seal Attic Bypasses & Penetrations
Why it matters
Unsealed attic bypasses account for 15–30% of whole-home heating/cooling loss, costing $500–1500+/year in wasted energy. Air sealing also eliminates ice dams (warm attic + cold roof = frozen gutters). This is the #1 cost-effective efficiency retrofit (ROI typically 1–3 years).
Stop forgetting to do this.
Hearth generates a personalized maintenance schedule so you never miss another air seal attic bypasses & penetrations.
How to do it
- 1
Hire a certified energy auditor to perform a blower door test ($300–500); results identify pressure-driven leakage.
- 2
Review the auditor's report for attic-related findings (rim joist, duct leaks, bypass locations).
- 3
Common bypass priorities: rim joists (largest single leak), exhaust vents, recessed light cans, attic hatch gasket.
- 4
Seal rim joists with spray foam or mineral wool + caulk; do not block soffit ventilation.
- 5
Install damper-sealed ducts or seal with mastic + fiberglass mesh at every penetration in attic.
- 6
Conduct post-retrofit blower door test to verify air-tightness improvement (typical improvement 10–25%).