Research · Room coverage
Air Purifier Room Size: CADR and Coverage Across 247 ENERGY STAR Records
The median reported room area is 250 ft². But a coverage number only becomes comparable when the ceiling height, CADR type and equivalent air-change rate are specified.
ENERGY STAR V3.0 · Captured 2026-10-20 (UTC) · 247 eligible records · Analysis of certification data, not independent testing
Why the same purifier can have different coverage numbers
Calculated area (ft²) = smoke CADR (cfm) × 60 ÷ (eACH × ceiling height in feet). eACH means equivalent air changes per hour from clean-air delivery, not outdoor ventilation. At an 8 ft ceiling, 200 cfm gives 312.5 ft² at 4.8 eACH, or 1,500 ft² at 1 eACH. Increasing the ceiling to 10 ft reduces the 4.8 eACH area to 250 ft².
The 4.8× ratio follows directly from the formula; it is not a new experimental finding or evidence that manufacturers use a 1 eACH claim. We have no verified retail claims and make no manufacturer-discrepancy rankings. Neither scenario guarantees a health outcome.
Distribution of reported room sizes
| Reported area | Records |
|---|---|
| 0–<100 | 27 |
| 100–<200 | 47 |
| 200–<300 | 57 |
| 300–<400 | 32 |
| 400–<500 | 35 |
| 500–<600 | 27 |
| 600–<800 | 16 |
| 800+ | 6 |
Reported area is not our calculated area
Using smoke CADR, 4.8 eACH and an 8 ft ceiling, our calculated areas are 0.2% to 1.6% above the reported areas in this snapshot; the median is 0.8%. The differences are small but systematic. Rounding and rating conventions are possible explanations; this comparison does not establish their cause or a data error.
Below: five records with the largest absolute percentage differences, not a product ranking. Difference = (calculated − reported) ÷ reported × 100. No tolerance is used to declare a record “correct” or “incorrect”.
| Model / source ID | Smoke cfm | Reported ft² | Calculated ft² | Difference |
|---|---|---|---|---|
| GoveeLife H7126 ID 4016425 | 39 | 60 | 60.9 | +1.6% |
| Bionaire BAP9260 ID 4529281 | 46 | 71 | 71.9 | +1.2% |
| Afloia Kilo ID 4515858 | 79 | 122 | 123.4 | +1.2% |
| Clorox 11101 ID 4005671 | 79 | 122 | 123.4 | +1.2% |
| Ikea E2111 ID 4587247 | 44 | 68 | 68.8 | +1.1% |
Inclusion rules and reproducibility
The retrieval returned 247 source records. We included 247 with finite, positive smoke CADR and reported room area; 0 were excluded. Each row represents an ENERGY STAR ID, not necessarily a distinct product family. No weighting or brand deduplication is applied. Statistics describe this certification snapshot, not all purifiers or market share.
The CSV preserves full calculation precision. Displayed figures round to one decimal place. The archived source contains the parsed rows retrieved from the public feed, and the manifest records retrieval times, queries, counts and SHA-256 checksums. The earlier snapshot had no documented capture date; this dated retrieval replaces it. Count and unique-ID checks cannot prove the source stayed unchanged throughout retrieval.
What this study cannot tell you
We did not measure noise, room mixing, pollution removal in occupied homes, performance at quiet settings, gases, filter life or medical benefits. Coverage is a sizing calculation, not a guarantee. Certification dates are not snapshot dates. This analysis has not received independent review and is not presented as peer-reviewed.
Sources: ENERGY STAR public dataset, ENERGY STAR buying guidance, and AHAM sizing guidance. These sources do not endorse PureAirIndex.