How to Change Air Purifier Filter? | Straightforward Steps

An air purifier only cleans the air when its filter is actually working, and a clogged filter wastes energy while letting particles slip back into the room. The process for changing an air purifier filter is similar across most brands — turn the unit off, unplug it, open the filter door, remove the old filter, and install the new one exactly as the old one sat. The steps below cover the general process plus the specific instructions for Philips, Dyson, and Filtrete models.

The General Filter Swap, Step by Step

Start by turning the unit off and unplugging it from the wall. Opening the filter compartment while the unit is live is the most common mistake people make.

• Turn the purifier off and unplug it.
• Open the filter compartment — usually a rear panel or side door that slides or unclips.
• Remove the old filter. If it has a tab, pull it straight out; don’t twist or force it.
• Take the new filter out of its box and remove ALL plastic wrapping and tape. This step matters more than it seems — a filter still wrapped in plastic purifies nothing.
• Install the replacement in the same orientation as the old one. Most filters have arrows or labels showing which side faces the fan.
• Close the compartment securely, plug the unit back in, and reset the filter indicator if the model has one.

After you turn the purifier back on, run it at the highest fan speed for a few minutes to confirm airflow feels normal. If the unit sounds strained or the filter door won’t seat flush, the filter is probably seated wrong — pull it out and try again.

Brand-Specific Steps for Philips, Dyson, and Filtrete

Each major brand has its own exact sequence for changing the filter, and these differences matter because some models add a reset step or a unique filter-seating requirement. Philips instructs users to turn off and unplug the purifier, remove the used filter when the filter alert light comes on, discard it, remove all packaging from the new filter, and place it into the purifier. To reset the filter lifetime counter, touch and hold the child lock button for three seconds.

Dyson says to always unplug the machine before changing filters. The company’s carbon-filter replacement video shows the full sequence: remove the plug from the wall, release the purifier head, remove the outer casing and the old filter, unwrap the new carbon filter, clip it onto the inner core, reassemble the head, and reconnect power. Dyson also notes that old filters should be disposed of according to local codes and regulations.

Filtrete’s install guide walks through a slightly different process. Turn off the purifier, remove the rear filter cover, and remove the used filter using the bottom tab. On Smart Air Purifiers, the new filter must be inserted at an angle so it sits parallel with and on top of the grill — this angled insertion is a requirement, not a suggestion. Replace the door, then hold FILTER for three seconds to reset the tracker. Filtrete’s traditional Room Air Purifiers use a RESET button held for three seconds instead.

Filtrete’s pre-filters also need attention. Remove the pre-filter screens, vacuum them or rinse with water, and make sure they are completely dry before reinstalling.

Common Mistakes and What to Avoid

Most filter-change failures trace back to three simple errors, and avoiding them takes seconds. First, never skip unplugging the unit before opening the filter compartment — it’s a safety step, not a formality. Second, never install a filter with packaging still on it; Philips explicitly instructs removing all packaging material first, and a wrapped filter simply won’t clean air. Third, never force a filter into place. Filtrete notes that some pre-filters only fit their respective sides, so if it won’t seat, check orientation before pushing harder.

One more step gets forgotten more than any other: resetting the filter-life indicator. If your model doesn’t get its timer reset, the light will keep telling you to change the filter even though you just did. If a filter door won’t close or the unit makes a new noise after reassembly, reseat the filter before doing anything else.

If you’re shopping for replacement filters, our tested roundup of the best air purification filters compares the top options across brands and price points.