Room by Room · reference
Air Purifier for a Open-plan space: What Size You Need
for a 500–600 sq ft open-plan zone
EPA table, 600 sq ft row · 8-ft ceiling · the last published row
An open-plan zone between the 500 and 600 sq ft rows takes 390 cfm, the largest minimum EPA publishes, at an 8-foot ceiling. If your space is bigger than that, the arithmetic stops, because the table does.
Open plan breaks the table in two ways: the floor area outgrows the last row, and ceilings in converted spaces often rise past the 8-foot assumption. The honest response is not a bigger number invented for the box. It is zoning.
What the published table gives an open-plan space#
Between 500 and 600 sq ft, the minimum is 390 cfm. That row is the ceiling of the published table as well as the last figure in it.
| Room area | Minimum CADR |
|---|---|
| 100 sq ft | 65 cfm |
| 200 sq ft | 130 cfm |
| 300 sq ft | 195 cfm |
| 400 sq ft | 260 cfm |
| 500 sq ft | 325 cfm |
| 600 sq ft | 390 cfm |
Where the table ends#
Past 600 sq ft, no stated minimum exists. EPA’s guide does not extrapolate, and neither will this page: there is no honest number for a 900 sq ft living space, only the refusal to invent one.
The published alternative is architectural: treat zones as rooms. Kitchen zone, sofa zone, desk zone, each with its own floor area and its own published row.
Zones are rooms#
One unit per zone, sized to that zone’s floor area, is the defensible plan. The cooking zone works hardest, so it earns the highest smoke CADR you can find, cooking smoke is the finest-particle event in most homes.
Open plan has few doors, which is precisely why zones work better than one heroic machine: air responds to distance and furniture more readily than to a floor plan’s ambition.
Large-room units placed per zone beat a single machine sized to nobody’s published row.
Suggested next step
Compare what the table asks for
Search listings for the published minimum your room needs, then check the smoke CADR on the shortlist before anything else.
Placement and running#
- Mid-zone, with clearance on every side, not in the walking line between zones.
- Out of direct sun where a glazed wall turns afternoon into an oven.
- Run the cooking-zone unit whenever the hob is on and for a while after it stops.
- Ceilings higher than 8 ft? EPA says you may want a higher CADR, the assumption is the table’s, not yours to inherit silently.
What the box leaves out#
A "whole-floor" coverage claim has no published backing. The table is per room and stops at 600 sq ft; any figure for more floor is marketing arithmetic.
And the smells of open plan, coffee, cooking, the sofa’s history, are gases, unrated. The rated work is particles, zone by zone.
Questions people actually ask
Sources
- U.S. Environmental Protection Agency, Guide to Air Cleaners in the Home (2nd edition), retrieved 2026-08-30
Quoted and transcribed, never paraphrased into new numbers. This site does not interpolate between published figures.
Suggested next step
One more angle before you decide
The minimum is settled, spend the rest of the decision on noise, filter cost and the smoke CADR.
Get the next sizing brief
One email when a page earns its figure. No deal alerts, this site does not show prices.
Printed from https://roomandfilter.com/rooms/air-purifier-for-a-open-plan-space, “Air Purifier for a Open-plan space: What Size You Need”. Figures from U.S. Environmental Protection Agency, Guide to Air Cleaners in the Home (2nd edition), retrieved 2026-08-30. No prices are shown on this site, by policy.