Stop Wasting Money Cooling Your Attic, by Pat's DIY Insider on YouTube. 8 min 45 s.
- Video length
- 8 min 45 s
- Time to do it
- About 1 hour
- Difficulty
- Easy
- Steps
- 8
What you need
Steps
Compare room temperatures on a hot afternoon. A room that never keeps up with the rest of the house often sits at the end of a leaking or crushed duct run.
Test airflow at each register. Hold a tissue against the grille or use an airflow meter. Weak or uneven flow points to a leak or a kink behind the vent.
Note smells and dust coming from the vents. Musty or dusty air from one register can mean attic air is being pulled into the duct through a gap.
Go into the attic in the cool morning, not at midday. Wear gloves, a dust mask and long sleeves, and use a steady ladder. Attics get dangerously hot fast.
Inspect the duct runs with a flashlight. Look for disconnected joints, torn flex duct, crushed sections and gaps where the ducts meet the air handler.
Run the system and feel along each joint with your hand. Escaping cold air shows a leak fast. Mark every spot with tape or a marker.
Seal small gaps with duct mastic or UL 181 foil tape. Press the tape down firmly and wrap the joint fully. Never use cloth-backed duct tape, it fails in attic heat.
Recheck airflow at the registers once the seals are dry. If flow is still weak, call an HVAC technician to test and balance the whole system.
Tips and common mistakes
Turn the system off before sealing so the blower does not push air through wet mastic.
Keep at least 2 inches of clearance between ducts and the flue or any heat source.
Check the attic access panel and any top plates while you are up there, since air leaks there waste just as much money.
Take photos of each joint before you seal it, so a technician can see the layout later.
Questions
How do I know if my ducts are leaking in the attic?
Hot rooms, weak airflow at some registers, dusty or musty air and high summer bills are the usual signs. Feeling cold air escape at a joint while the system runs confirms it.
Can I seal duct leaks myself?
Yes, small gaps at accessible joints are a good DIY job with foil tape or mastic. Large tears, crushed runs or leaks near the air handler are better left to an HVAC technician.
Is foil tape better than duct tape for ducts?
Yes. UL 181 foil tape holds up to attic heat, while cloth-backed duct tape dries out and peels off within a season or two.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
