How we compare air purifiers
AirSheet is a spec sheet and a room matcher, not a test lab. We collect each brand's published figures, re-check them on a schedule, size every model by the same standard and rank by the numbers.
What is listed
23 air purifiers from Levoit, Blueair and Coway. A model is added once its clean air delivery rate (CADR) and US price can be confirmed, and removed when it is discontinued. This is not every air purifier on the market.
Where specs come from
CADR, noise, power use and filter details are the brand's published specs. Each purifier page links to its source and shows the date the specs were last verified; two purifiers are re-checked every day, oldest first. Where a brand does not state how long a filter lasts, we assume 6 months.
Prices
Price and stock are read from each brand's own store every day. Each purifier page shows the date its price was checked.
Room size and running cost
Room size is the largest room a purifier can clean 4.8 times an hour with 8 ft ceilings, the standard behind AHAM room ratings, calculated from its smoke CADR. Yearly running cost is replacement filters on the brand's schedule plus electricity at $0.17 per kWh. Both are our calculations from published figures, not lab tests.
Other filters and pre-filters
Smoke, pet, allergen and odor versions of a filter, and pre-filters, are listed on a purifier's filter page only where the maker's own listing names that model. The page quotes that wording, links to it and shows the date we last found it there; a script re-checks every pairing and price daily. The type shown is the maker's description. We have not tested these filters, the purifier's CADR is published for its standard filter, and we do not list third-party filters.
Rankings
Every "best" pick is computed. Best value is the lowest price per cfm of smoke CADR. Cheapest to run is the lowest yearly filter and electricity cost per cfm. Quietest is the lowest noise on the lowest setting.
General information, not medical advice.
What we do not do
- We do not test products hands-on, and nothing on this site is presented as a test result.
- We do not accept payment for placement, and commission rates are never an input to a ranking.
- We do not publish user reviews or star ratings.
Corrections
If a number on this site is wrong or out of date, tell us at corrections@buyersheet.com and we will check it against the source.
How the site earns money
Some links to retailers are affiliate links, which can pay us a commission when you buy, at no extra cost to you. Details are in the affiliate disclosure.