Symptoms
- Filter looks gray, matted, or covered in dust and pet hair
- Weak airflow from vents
- AC may be icing up or running longer than usual
Likely causes
- CommonFilter overdue for replacementStandard filters typically need replacing every 1–3 months depending on household dust and pets.
- PossibleWrong filter thickness or MERV rating restricting airflowA filter too restrictive for the system can choke airflow even when relatively new.
- PossibleHeavy pollen season or nearby construction dust clogging it fasterSeasonal or environmental factors can clog filters faster than normal.
What to do
- Turn the AC off before removing the filter.
- Slide out the old filter, noting the airflow direction arrow printed on its frame.
- Hold it up to a light; if you can't see light through it, it needs replacing.
- Insert the new filter with the airflow arrow pointing toward the air handler, matching the old one's orientation.
- Write the install date on the new filter frame with a marker to track replacement timing.
- Check monthly during cooling season and replace every 1–3 months, or sooner with pets or allergies.
Tools and parts
AC air filter, correct sizeSearch: “central air filter size MERV replacement”
When to call a pro
This is a simple DIY task; a professional is only needed if the filter housing itself is damaged or hard to access.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.