Should I Be Worried If My Air Filter Turns Black in Two Weeks

Side-by-side comparison of a clean white HVAC filter and a heavily clogged black filter with a gloved hand pointing to the grime.

If your air filter has gone from white to black in under two weeks, your HVAC system is trying to tell you something — and in our experience working with South Florida homeowners, ignoring it usually leads to bigger problems down the road. Some darkening is normal. A filter that turns black that fast is … Read more