Replacement Air Filters: HEPA, Carbon and Wick

Fit before filtration: matching the code, size and shape

A filter works only if it fits the unit it was designed for, so start with the model-specific code in your manual or printed on the old filter, then check the dimensions. Listings give the height, width and thickness: a filter even a little undersized lets unfiltered air slip around the edges. Multi-packs and combination sets usually cover several stages, so confirm the pack contains each layer your unit expects.

Not everything here is for room units. Respirator cartridges for organic vapor and acid gas protect a person wearing a mask, and a dust filter sized for a 120 mm fan is meant for a computer case, not a room unit. Where a rating like MPR appears, a higher number means the filter captures smaller particles but also restricts airflow more, which matters for a unit with a weak fan.

HEPA, carbon or wick: what each media is for

HEPA media traps particles such as dust, pollen and pet dander; a True HEPA grade is rated to catch 99.97 percent of 0.3 micron particles. Activated carbon works on odors and some gases rather than particles, which is why many purifier filters layer the two. A wick filter belongs in an evaporative humidifier, where it soaks up water and collects minerals, and it needs replacing when it turns stiff, discolored or smelly. Note which intended use the listing states: air purifier or humidifier.

Questions about Replacement Air Filters: HEPA, Carbon and Wick

How do I find the right replacement filter for my unit?

Use the filter code in the manual or printed on the old filter and match it exactly, then confirm the dimensions. A look-alike that is slightly smaller or thinner leaves gaps, so air bypasses the media and the filter does far less than you expect.

How often should a filter be changed?

Follow the interval in the manual, then adjust. Pre-filters and carbon layers wear out sooner in homes with pets, smoking or cooking. Replace any filter early if airflow drops, odors come back, or it looks gray and clogged.

Can I wash and reuse a HEPA filter?

Generally not. True HEPA media is damaged by water and handling, and washing reduces its efficiency. Only filters labeled washable, usually coarse pre-filters, should be rinsed, and they must be completely dry before going back into the unit.