August 20, 2025 · 5 min read
1. Cheap fiberglass filters
The flat $2 fiberglass filters at the hardware store are designed to protect the equipment, not your air. Switch to a pleated MERV 8–11 filter and change it every 60–90 days. You'll feel the difference within a week.
2. A dirty evaporator coil
Your AC's evaporator coil sits inside the air handler and is constantly wet during cooling season. Combine moisture with dust and you get mold — pumped through every room.
3. Leaky ducts in unconditioned spaces
Ducts that run through attics, basements, and crawlspaces leak both ways. They lose conditioned air and they suck in whatever's around them — including spores and dust.
4. Bathroom and kitchen exhaust fans that don't actually vent
More common than you'd think — fans terminate in the attic or never actually move air. Moisture and cooking byproducts stay in the home.
5. Humidity that's too high or too low
Aim for 40–50% relative humidity year-round. Too high feeds mold; too low irritates lungs and sinuses.
Related service
Air Duct Cleaning
Remove built-up dust, allergens, and debris from your ductwork for fresher indoor air.
See Air Duct Cleaning details