About Room & Filter

The short version

Almost every air purifier page answers a sizing question with a coverage claim, “covers up to 1,500 sq ft”. Coverage claims are marketing; nobody standardises the conditions behind them. The EPA publishes an alternative: one minimum clean air delivery rate per room size, in a short table that fits on an index card.

This site reads that table, and nothing else, for every sizing answer. It is also honest about what the table does not contain: there is no published CADR for gases, odours or VOCs, and MERV is not a room-size rating. Those two refusals appear on every relevant page, because they are the two places marketing most often implies a number that does not exist.

What the site is

• 100 pages across five pillars, sizing, room by room, pollutants, filters, and buying equipment.
• Six pages built directly from the six published EPA rows. If a row leaves the dataset, the page leaves the site.
• One interactive CADR tool that rounds up between published sizes and refuses everywhere it has no figure.
• Every figure carries its citation on the page, above any affiliate link. Sources are quoted, never paraphrased into new numbers.

How the money works

Room & Filter is an affiliate site. When a page suggests what to look for, links may earn a commission at no extra cost to you. The rules that govern it:

• The disclosure renders above the first affiliate link on every page, not buried in the footer.
• No price appears anywhere, not in a title, table, sentence or alt text. Amazon restricts price display to their own tools, and the policy is followed strictly.
• One filled suggestion per screen. The answer comes before the commerce, every time.
• Category links only. No ASINs, no “best model” verdicts, no products this project has not verified.

The source of record

Every published figure traces to the Guide to Air Cleaners in the Home (2nd edition) (U.S. Environmental Protection Agency, retrieved 2026-08-30). Where a page needs a figure this project does not hold, the page says so, it does not get written with an invented number.