HEPA Filter Replacement: When and How to Swap Yours

By Osmo -Seth Medical Group LLC | Published: 2026-10-28

Category: How-to Guides

Learn when to replace your HEPA filter, how to swap it safely, and what to check to keep your air purifier performing at its best.

Quick answer

Replace your HEPA filter every 6 to 12 months, or sooner if you notice reduced airflow or a musty smell. Follow the steps below to swap it safely and keep your air purifier running efficiently.

Why filter lifespan varies

HEPA filter lifespan depends on usage hours, air quality, and how often you run the purifier. A filter in a dusty home or near a busy street will clog faster than one in a cleaner environment. Check the manufacturer's guidance for your specific model, but treat 6 to 12 months as a general range.

Replacing too early wastes money; replacing too late reduces performance and can strain the fan. If you notice a drop in airflow or a stale smell before the typical interval, it's time to swap.

What to check before ordering a replacement

Always confirm the filter model and compatibility with your air purifier before buying. Some filters come in multi-packs, like Osmo's 2x Additional HEPA Filters, which can be convenient if you have multiple units or want a spare. Check the SKU and dimensions against your purifier's manual to avoid ordering the wrong part.

How to replace your HEPA filter

Turn off and unplug the purifier: Always power down and unplug the unit before opening the filter compartment. This prevents electrical shock and accidental fan start-up. Never attempt filter changes while the unit is plugged in.
Remove the old filter: Open the filter cover and carefully slide out the old HEPA filter. Note how it sits so you can insert the new one the same way. Dispose of the old filter according to local waste rules. Check the old filter for debris buildup; heavy dust may indicate you should replace it sooner next time.
Insert the new filter: Unpack the new filter, remove any plastic wrapping, and place it into the compartment, ensuring the arrows or labels face the correct direction. Close the cover securely. Make sure the filter is seated fully; a loose fit can allow air to bypass the filter.
Reset the filter indicator (if applicable): If your purifier has a filter replacement light or timer, reset it according to the manual. This helps track the next replacement interval. Note the replacement date on the filter or in a calendar to stay on schedule.
Run the purifier and check airflow: Plug the unit back in, turn it on, and run it at high speed for a few minutes. Confirm that airflow feels strong and no unusual noises come from the unit. If airflow seems weak, double-check the filter orientation and seal.

Replacement filter options

2x Additional HEPA Filters: This listing is for 2x Additional HEPA Filters from Osmo, offered as a two-filter pack (SKU HEP001-02-CXXX). Buying a two-pack saves you from reordering mid-cycle and is handy if you have more than one compatible unit.
2x Additional HEPA Filters