Ductwork
Poorly installed ductwork is a major source of energy loss in homes, so this section focuses on the most common issues found during building commissioning. The problems seen most often are under-insulated ducts and boots that are not properly sealed to drywall or flooring.
Some critical details to note:
- R4.2 duct insulation is not permitted in vented attics or uninsulated basements.
- Duct boots should always be sealed to the finished surface before registers are installed.
Ductwork Requirements
- All duct connections and seams must be sealed using UL-181 rated foil tape or mastic.
- Seal duct penetrations at drywall and floor openings to prevent air leakage.
- Minimum R-6 insulation required for ducts in unconditioned basements or crawlspaces.
- Minimum R-8 insulation required for ductwork located in exposed attics.
