Size a Room

Size a Room for an Air Cleaner

Determining the size of your room is as simple as measuring how wide and long it is (Room Width x Room Length = Total Square Feet). To determine your Room Volume, simply multiply the Total Square Feet by the Room Height (Total Square Feet x Room Height = Room Volume).

To choose which air cleaner you need you must look at the Room Volume and compare it with the Air Cleaner Flow Rate. The Air Cleaner Flow Rate will help you acheive your desired level of air quality based on the Air Changes Per Hour (ACH). Indoor air quality professionals and Allergists recommend 3 - 6 ACH for each room.

To determine how much air must be moved through the air cleaner to provide 3 ACH, you take the Room Volume and multiply by 3 (Room Volume x 3 = Total Volume of Air). Air cleaners provide air flow performance in cubic feet per minute, so you must take your Total Volume of Air to achieve 3 ACH and divide by 60 minutes to get a value for cubic feet per minute (cfm) (Total Volume of Air / 60 = Air Cleaner Flow Rate (in cfm)).

Use the chart below to determine the Air Cleaner Flow Rate you need.

Room Size (square feet)	Air Cleaner Flow Rate to Achieve 3 ACH	Air Cleaner Flow Rate to Achieve 6 ACH
75 sq. ft.	30 cfm	60 cfm
100 sq. ft.	40 cfm	80 cfm
125 sq. ft.	50 cfm	100 cfm
150 sq. ft.	60 cfm	120 cfm
175 sq. ft.	70 cfm	140 cfm
200 sq. ft.	80 cfm	160 cfm
225 sq. ft.	90 cfm	180 cfm
250 sq. ft.	100 cfm	200 cfm
275 sq. ft.	110 cfm	220 cfm
300 sq. ft.	120 cfm	240 cfm
325 sq. ft.	130 cfm	260 cfm
350 sq. ft.	140 cfm	280 cfm
375 sq. ft.	150 cfm	300 cfm
400 sq. ft.	160 cfm	320 cfm
425 sq. ft.	170 cfm	340 cfm
450 sq. ft.	180 cfm	360 cfm
475 sq. ft.	190 cfm	380 cfm
500 sq. ft.	200 cfm	400 cfm
525 sq. ft.	210 cfm	420 cfm
550 sq. ft.	220 cfm	440 cfm
575 sq. ft.	230 cfm	460 cfm
600 sq. ft.	240 cfm	480 cfm
625 sq. ft.	250 cfm	500 cfm