Air purifier sizing for a kitchen

Researched from the AHAM AC-1 test method, EPA and CARB guidance, and published manufacturer specifications

Quick answer

A kitchen is sized at 6 air changes an hour against a 8 foot ceiling on this site, so a 200 square foot one needs about 160 CFM of clean air delivery. The table below runs from 100 to 350 square feet.

Required CADR by floor area, 8 foot ceiling
Floor area	Volume	At 2 ACH	At 6 ACH	At 6 ACH
100 sq ft	800 cu ft	27 CFM	80 CFM	80 CFM
120 sq ft	960 cu ft	32 CFM	96 CFM	96 CFM
150 sq ft	1,200 cu ft	40 CFM	120 CFM	120 CFM
175 sq ft	1,400 cu ft	47 CFM	140 CFM	140 CFM
200 sq ft	1,600 cu ft	53 CFM	160 CFM	160 CFM
250 sq ft	2,000 cu ft	67 CFM	200 CFM	200 CFM
300 sq ft	2,400 cu ft	80 CFM	240 CFM	240 CFM
350 sq ft	2,800 cu ft	93 CFM	280 CFM	280 CFM

Meets 160 CFM, the medium room class

WINIX 5510 Air Purifier (New Generation of 5500-2 with App Support) for Home Large Room Up to 1881 Ft2 in 1 Hr, True HEPA, High Deodorization Carbon Filter and Auto Mode, Captures Pet Allergies, Smoke

This machine can be credited with about 502 CFM, derived from the listing's own figures: 1881 sq ft at 2 air changes an hour, assuming an eight foot ceiling. That clears the 160 CFM this room calls for.

$179.99Check pricePrices change often

Check the noise at the speed that delivers the airflow, not the figure quoted for the lowest setting.

Every size in this room type

100 sq ft 80 CFM needed
120 sq ft 96 CFM needed
150 sq ft 120 CFM needed
175 sq ft 140 CFM needed
200 sq ft 160 CFM needed
250 sq ft 200 CFM needed
300 sq ft 240 CFM needed
350 sq ft 280 CFM needed

What makes a kitchen different

The usual sources in this room are frying and searing, which produce fine particles in quantity, toast and grilling, gas hob combustion products. That mix is what decides whether the carbon stage matters as much as the particle stage, and it is why the same square footage in two different rooms does not always call for the same machine.

Cooking is the fastest way to spike particle counts in a home, and the numbers a monitor shows during a fry up surprise most people. Run the extraction hood on the back burners, and treat the purifier as the thing that clears what is left rather than as the primary control.

Which air change target this room is sized at

This section sizes a kitchen at 6 air changes an hour, the smoke and wildfire season case, which suits wildfire smoke, a woodstove that backpuffs, or smoke drifting in from outside. Two changes an hour is the comfort baseline and six is where smoke guidance sits.

The target is guidance rather than a measured threshold, so it is worth knowing what moving it does. Going from two changes an hour to 6 multiplies the airflow you need by 3, and the noise and the filter cost move with it.

Machines sized for this room

Each of these publishes either a CADR or a coverage claim with the air change rate behind it, so it can be compared against the requirement above.

MOOKA
MOOKA H13 HEPA Air Purifier for Home Pet Large Room Up to 1300ft2, Black
- HEPA claimed
- carbon stage
- has a UV lamp
$46.98 Check price
Prices change often
MOOKA
MOOKA Air Purifiers for Home Room up to 1076ft2, True HEPA Filter, B-D02L
- HEPA claimed
- carbon stage
$49.99 Check price
Prices change often
MOOKA
MOOKA Air Purifiers for Home Room up to 1076ft2, True HEPA Filter, B-D02L
- HEPA claimed
- carbon stage
$49.99 Check price
Prices change often
Afloia
Afloia Air Purifier for Large Rooms Up to 2,000 Sq. Ft. with PM2.5 Display
- carbon stage
- washable pre-filter
- particle sensor
- auto mode
$79.99 Check price
Prices change often
HEAPETS
Pet Air Purifier for Home Large Room 2500 Sq Ft, H13 HEPA Double-Sided Filter with Washable Pre-filter, Adsorbs Pet Hair Dander Odor Allergies Smoke Dust,PM2.5 Air Quality Monitor,Auto Mode,P358 Grey
- HEPA claimed
- carbon stage
- washable pre-filter
- auto mode
$99.99 Check price
Prices change often
KNKA
KNKA Air Purifiers for Home Bedroom Up to 1,695 Ft2 in 1 Hr, APH4000, White
- carbon stage
- washable pre-filter
- particle sensor
- auto mode
$119.97 Check price
Prices change often

Common questions

What size purifier does a kitchen need?

Multiply the floor area by the ceiling height, multiply by the air changes an hour you want, and divide by sixty. At 8 feet and 6 changes an hour, a 120 square foot kitchen needs about 96 CFM and a 350 square foot one needs about 280 CFM.

Should I buy one large unit or two smaller ones?

Two smaller machines usually mix a room better than one large one, because a single unit recirculates its own clean air in the corner it sits in. One larger machine is quieter for the same total airflow and costs less to keep in filters. If the room is long or L shaped, two is the better answer more often than the arithmetic alone suggests.

Does the door being open change the sizing?

It does, and by more than people expect. An open door connects the room to a hallway and often to a stairwell, and the machine is then serving that whole volume rather than the room on the floor plan. Either size for the connected space or close the door during the hours that matter.

Is a higher air change rate always better?

No. Airflow costs noise, power and filter life, and past a point the room is already as clean as the filter can make it. The honest ceiling is the arrival rate of whatever you are removing: on a smoke day more is genuinely better, and on an ordinary day in an ordinary house it is not.

Do these figures assume anything about the filter?

They assume the machine delivers its rated clean air delivery rate, which a clogged filter does not. A filter at the end of its life moves less air at the same fan speed, so the effective air change rate drops quietly over months without the machine sounding any different.