How to read this site
Evidence you
can question.
We preserve source claims, their context and their limits. A readable photograph verifies what was printed. It does not independently establish laboratory performance.
Four different kinds of information
- Manufacturer claims: values transcribed from a specific package or document, with source IDs and conditions retained.
- Verified transcription: a source-image readback checked the numerical reading. It is not a second experiment.
- Practitioner guidance: attributed field experience, including Better Air’s practical recommendations.
- Estimates and open questions: labeled separately, never silently promoted to measurements.
Pressure comparisons
Compare the same product size, revision, media or assembly and compatible test conditions. Plot actual points with airflow in CFM and pressure in inches of water column. Keep document/media/cabinet tables separate. Missing 1,000-CFM data stays missing. This release does not interpolate or extrapolate.
Corrections stay visible
Filtrete 1550’s printed 0.013 is owner-confirmed erroneous; the intended value is unknown, so the photographed curve is held. Honeywell P01’s 683-CFM reading is corrected to 0.054 with the original reading and receipt preserved privately. AprilAire 113/610/613/913 document conflicts, the 413 label anomalies, 410 PSE flag and BestAir depth conflicts remain classified rather than silently resolved.
HDX FPR 7 / P05 has a source discrepancy: its photographed package prints MERV 11, while the matching Home Depot SKU listing retrieved October 31, 2026 states MERV 10. The cause is unresolved. FPR 9 / P06 prints MERV 11 and its matching listing agrees. No universal FPR-to-MERV conversion is applied.
Capture and clean-air interpretation
ASHRAE 52.2 characterizes size-resolved particle removal. MERV is not an exact all-particle efficiency. An idealized removal-rate proxy must define actual airflow, particle-specific capture, bypass and runtime. It is not certified CADR or a room-exposure prediction. No numerical purifier-equivalent tool is released.
Primary scientific references
- EPA: What is a MERV rating?
- EPA: Air cleaners and air filters in the home
- ASHRAE Journal: How do particle filters work?
Historical 2021 gross-room-decay clean-air estimates are preserved separately, not presented as certified CADR or testing of the photographed 2026 specimens.
Publication and independence
Only individually approved, cropped and metadata-sanitized photographic derivatives are published. Original photographs, private metadata and restricted manufacturer PDFs remain private. Official document links may lead to a different revision from the archived source. Research listings are brand-neutral; purchase guidance is separate and does not imply compatibility from a shared nominal size.