Indoor air is often more polluted than the air outside, and the EPA ranks it among the top environmental health risks. Most of the fix is maintenance you already own: a fresh HVAC filter is the single biggest lever, since a loaded filter stops cleaning air and starts choking airflow. Clean vents and a radon test cover the rest.
Quick indoor air quality checklist
- Change the HVAC filter on schedule.
- Replace the air purifier's HEPA filter.
- Deep-clean the dryer vent.
- Clean the range-hood grease filter.
- Clean the bathroom exhaust fan.
- Clean the humidifier tank.
- Test radon levels.
Change the HVAC filter
The furnace or air handler filter is the main thing pulling dust, pollen, and dander out of the air your whole house breathes. Check it monthly and replace it when it looks gray. A higher-MERV filter captures finer particles, but only up to what your system is rated to handle.
Replace the air purifier's HEPA filter
A HEPA purifier only cleans the air while its filter has capacity left. Replace it on the schedule for your model, since a saturated filter restricts airflow and stops catching particles. Check the model number for the right replacement size.
Deep-clean the dryer vent
Lint that escapes the screen builds up in the duct, pushing humid, particle-laden air and raising fire risk. Clean the screen every load and clear the full duct at least yearly so it vents properly to the outside.
Clean the range-hood grease filter
Cooking is a major indoor source of fine particles. A grease-clogged hood filter can't pull them out, so degrease the metal mesh filter in hot soapy water every month or two and run the hood whenever you cook.
Clean the bathroom exhaust fan
A dusty bathroom fan can't clear humidity and odors. Vacuum the cover and confirm it vents outdoors, not into the attic, so it removes the moisture that feeds mold.
Clean the humidifier tank
A dirty humidifier blows mold and bacteria into the air along with the mist. The EPA recommends emptying and drying it daily in use and cleaning it every few days with the maker's instructions.
Have the air ducts cleaned only when needed
The EPA does not recommend routine duct cleaning. Have ducts cleaned if there's visible mold, a vermin infestation, or heavy debris blowing out of the registers, not on a fixed schedule.
Test radon levels
Radon is the second leading cause of lung cancer in the US, and it's colorless and odorless, so a test is the only way to know. A short-term kit runs about $15 to $30. At or above the EPA action level of 4 pCi/L, have a certified contractor install mitigation.
What filters and purifiers can't do
Filters and air purifiers help with particles, but they don't replace the rest of the picture: opening windows when outdoor air is good, source control (no indoor smoking, low-VOC paint, vent gas appliances outside), and radon mitigation when a test calls for it. Treat the maintenance above as one leg of a stool, not the whole answer.
Good maintenance rhythm
The checklist gets you through the air-quality pass once. Keep things running smoothly all year round by following a regular maintenance schedule.
- Monthly: check the HVAC filter and replace it when dirty.
- Per the model schedule: replace the air purifier's HEPA filter.
- Every month or two: degrease the range-hood filter.
- Yearly: deep-clean the dryer vent and clean the bathroom exhaust fan.
- Daily in use: empty and dry the humidifier; clean it every few days.
- Every few years: retest radon, and after any foundation or HVAC work.