Follow the instructions and filter indicator for your exact purifier. A calendar interval is guidance, not a promise that every filter in every home will last the same time.
The first three records have different filter assemblies and schedules. Coway also separates the deodorization filter interval from the HEPA interval; do not replace or wash every layer as if it were one component.
The schedules for our initial references
These figures come from the linked manufacturer pages. Check your model instructions and use conditions before deciding.
| Filter | Guidance | What to keep separate |
|---|---|---|
| Levoit Core 300-RF | Replace about every 6–8 months | The linked Amazon option is one standard filter. |
| Coway 3304899 set | Deodorization: 6 months; HEPA: 1 year | The pre-filter is not included in the replacement set. |
| Blueair F2MAX | Up to 9 months, depending on use | The main filter and fabric pre-filter are different parts. |
Before buying the replacement
Read the complete model code and confirm the reference you already use. Check the pack contents before ordering, particularly when a manufacturer page shows a two-pack and the Amazon buying option is one filter.
Use the filter and cleaning instructions for your model when responding to its indicator. A replacement filter is not a diagnosis of a motor, fan or power fault.