Explore your space
How much clean air does your space need?
Explore how floor area, ceiling height and operating level affect clean-air delivery. Then see why room layout and airflow deserve a closer look.
Clean-air planning calculator
Same square footage. Different clean-air needs.
Length × width. Ceiling height changes volume, not floor area.
Calculate the CADR needed to maintain your target as room dimensions change.
Adjust the level. Maintain the rate.
Use + / − or enter your dimensions.
Enter a length between 5 and 100 ft in 0.5 ft increments.
Enter a width between 5 and 100 ft in 0.5 ft increments.
Enter a ceiling height between 6 and 40 ft in 0.5 ft increments.
5 is an illustrative starting point. Your eACH requirements may differ.
Enter a target between 0.1 and 30 eACH.
400 cfm is an editable example. Use the published CADR for the particle type and operating speed you plan to use. For multiple cleaners, add CADRs measured for the same particle type. CADR is not the fan airflow rating.
Enter a CADR between 0 and 10,000 cfm, or select “I don’t know the CADR.”
20 × 30 × 8 ft
What this result means
Your target requires 400 cubic feet of clean air per minute. Over an hour, that equals 5 times this room’s air volume.
Air mixes and recirculates, so this doesn’t mean every part of the room is cleaned 5 times.
To maintain 5 cleaner eACH
Same CADR as the starting example
What changes?
Adjust the operating level to match the room.
For example, at a target of 5 eACH, raising a 600-square-foot space’s ceiling from 8 to 12 feet increases required CADR from 400 to 600 cfm. A different operating level may meet that need. For Tatama, compare the result with measured CADR at each level.
CADR supports air cleaner comparisons under standardized test conditions. Neither CADR nor calculated eACH establishes air distribution or measured effectiveness in an occupied room.
Beyond the calculation · Spatial model
Air cleaning depends on where the air reaches
HVAC supply and return locations shape circulation. This illustration shows one possible path; actual airflow depends on the room and system.
- Illustrative HVAC path
- Illustrative particle source
Conceptual illustration, not to scale. Paths do not represent measured airflow or particle concentration.
Swipe to explore the room illustration →
Further reading: "The Crucial Role of Ventilation Effectiveness in Air Cleaning", International Filtration News.
Calculations, assumptions & sources
The calculator uses room volume and the cleaner's published CADR at the operating level you enter. These figures are planning estimates, not a measure of airflow or performance throughout an occupied room.
- Room volume
- Length × width × ceiling height, in ft³.
- Cleaner eACH
- CADR (cfm) × 60 ÷ room volume (ft³).
- Required CADR
- Room volume × target cleaner eACH ÷ 60.
Assumes a rectangular room and uniform ceiling height. HVAC and outdoor-air contributions are excluded. The 5 eACH starting target is illustrative. Placement, partitions and mixing can affect actual conditions. Air cleaning does not replace required ventilation.
Further reading: EPA air cleaner guide · Portable Air Cleaner Sizing Tool - Healthy Buildings at Harvard School of Public Health · AHAM Verifide air cleaner directory and sizing guidance · CDC/NIOSH ventilation FAQ.
From calculation to observation
What would you like to understand?
Select a question to explore a practical next step.
Compare monitored conditions before and after a documented change, while considering activities and other conditions. Pasoh can help reveal patterns worth investigating.
Explore Pasoh monitoring, a focused pilot or assessment, or Tatama equipment.