Filter replacement is based on usage and environment, not a fixed calendar date.
- Primary indicator: Replace the True HEPA filter when the "Check Filter" indicator light turns on and stays on.
- General guideline: Under normal household conditions, expect to replace the filter approximately every 12 months.
- Accelerated replacement factors: Replace more frequently (every 3-6 months) if used constantly (24/7), in a very dusty environment, in a home with multiple pets, or if you notice a significant drop in airflow.
IF THAT DIDN'T WORK: If the "Check Filter" light comes on immediately after installing a new, genuine Honeywell replacement filter, press and hold the Filter Reset button for 3-5 seconds to reset the indicator timer.
HEADS UP: Only use certified Honeywell replacement filters (Model HRF-300AP). Non-genuine filters may not fit correctly, reduce performance, or damage the unit.