Seal ducts and weatherstrip for free efficiency gains

Leaky ductwork wastes 20-30% of conditioned air before it reaches your rooms, according to the Department of Energy. Sealing ducts and weatherstripping doors/windows is the cheapest efficiency upgrade available.

Duct Sealing

1. Inspect visible ductwork in the attic, basement, and crawl space. Look for disconnected joints, visible gaps, and damaged insulation.
2. Seal joints with mastic sealant ($8-$12/tub) or UL-listed aluminum foil tape. Do NOT use standard cloth duct tape — it dries out and fails within 1-2 years.
3. Insulate uninsulated ducts in unconditioned spaces (attic, crawl space) with R-6 or R-8 duct insulation wrap ($20-$40 per roll).

Weatherstripping

1. Test doors: Close a dollar bill in the door — if it slides out easily, the seal needs replacing.
2. Replace worn weatherstripping: Frost King EPDM Cellular Rubber Tape (~$6-$10 for 17 ft) handles -40°F to 140°F and lasts 10 years.
3. Add or replace door sweeps ($10-$20 each).
4. Re-caulk exterior window frames where caulk is cracked. DAP Dynaflex 230 (~$6/tube) is paintable with 50-year flexibility.

Tips

• The DOE estimates proper duct sealing saves $120-$480/year on a typical energy bill
• A $30 investment in weatherstripping pays for itself within the first month
• Federal tax credits cover up to $1,200 for insulation and air sealing work