Fix the room assumptions
Use one measured room volume and describe doors, connected spaces and occupancy. Choose an explicit particle-cleaning assumption for the comparison.
A coverage figure may use a different ceiling height or number of air changes, so do not compare square-metre claims without their basis.
Use verified CADR at the intended speed
Hypothetical example: the room is 100 m³ and the planning assumption is four purifier-equivalent air changes per hour, requiring 400 m³/h. Candidate A states 450 m³/h at the intended speed; Candidate B states 600 m³/h only at maximum speed.
A would provide an estimated 4.5 equivalent changes per hour under a well-mixed assumption. B cannot be assessed at the intended speed until that evidence is supplied.
These candidates and values are illustrative, not verified products.
Compare the ongoing operation
Request the same noise quantity and conditions, filter replacement criteria, consumable quantities and common-period cost. If one response omits filter cost, label the total incomplete.
Acceptance should confirm the supplied configuration, installed filter, operating setting and documentation; a room-coverage label alone is not a performance demonstration.
Put it into practice
Your planning worksheet
A comparison table using consistent assumptions and verified specifications. On small screens, scroll the table horizontally.
| Common comparison field | Candidate A, illustrative | Candidate B, illustrative |
|---|---|---|
| Room volume used | 100 m³ | 100 m³ |
| CADR at intended speed | 450 m³/h, assumption for example | Not provided |
| Maximum-only CADR | Not needed for this comparison | 600 m³/h, assumption for example |
| Comparable at intended speed? | Yes, if evidence is verified | No; request paired data |
| Noise and filter cost | Obtain supporting evidence | Obtain supporting evidence |
Sources & context
- US EPA — Guide to Air Cleaners in the Home, second edition
Supports the distinctions between particle CADR, gas filtration, operating speed and clear airflow. Residential technical principles are used here for operational planning, not as workplace or clinical compliance criteria.
- US CDC / NIOSH — How Much Ventilation Is Enough?
Explains air changes and equivalent clean-air delivery. GAGE’s four-change examples are arithmetic illustrations, not this source’s recommended target; CDC discusses aiming for five or more total clean-air changes where possible in its stated context.
Sources checked 9 November 2026. Worksheets are editorial planning tools. Confirm site-specific requirements, current local guidance and the instructions for the equipment you use.
