Why is my upstairs so much hotter than downstairs?

Heat rises, attic ducts gain heat and returns are often undersized upstairs. Balancing and sealing usually help.

Can crawl space ducts cause humidity problems?

Yes. Leaky return ducts can pull damp crawl space air into the house.

Upstairs bedrooms, bonus rooms over garages and rooms with big west-facing windows often run hot. Balancing, sealing and better returns help.

Ducts under the floor can come loose, get torn by animals or sit in damp air. A disconnected run can blow cooled air straight into the crawl space.

Attic ducts sit in the hottest part of the house in summer. Sealing joints and adding insulation keeps more cooling where it belongs.

Poorly insulated ducts in humid crawl spaces can drip condensation, wetting insulation and wood.

Closed rooms without return paths stay stuffy. Transfer grilles or jumper ducts help air circulate.

A single system for two floors often struggles to keep the upstairs cool. Zoning or a second system may be worth considering.

Duct cleaning helps after renovations or pests, but sealing and insulation usually do more for comfort.

Tell the technician which rooms are uncomfortable. Send a request and an AC company will get in touch.

Keep supply registers and return grilles clear of furniture and rugs.

A technician can measure airflow at each register to find which rooms are short of air before changing anything.

Ducts in attics and crawl spaces should be insulated to stop heat gain in summer and condensation in humid weather.

Rodents and other animals can tear flex duct and insulation under the house. Check after winter.

Fixing ducts often makes a bigger difference to comfort than a larger AC.