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Large open living room: one air purifier or two?
Updated
Up to about 390 sq ft, one Levoit Vital 200S-P can do the job. Past that, use two units at opposite ends of the space. Two mid-size purifiers on medium are also quieter than one big unit running flat out.
First, measure the whole open area
If the living room, dining area and kitchen share one open space, they share the same air. Measure it all as one room. A 20 by 30 ft great room is 600 sq ft, not a 300 sq ft living room with a kitchen next to it.
Then check the ceiling. Box claims and our numbers assume 8 ft. High ceilings shrink every purifier.
| Setup | 8 ft ceiling | 10 ft ceiling | 12 ft ceiling |
|---|---|---|---|
| One Coway Airmega AP-1512HH | 360 sq ft | 290 sq ft | 240 sq ft |
| One Levoit Vital 200S-P | 390 sq ft | 310 sq ft | 260 sq ft |
| Two Coway units | 720 sq ft | 580 sq ft | 480 sq ft |
| Two Vital 200S-P units | 780 sq ft | 620 sq ft | 520 sq ft |
All figures are at 4.8 air changes per hour. Clean air delivery adds up, so two units cover about twice the area of one.
Why two units often beat one
- Coverage. One purifier in the corner of a long room cleans its own end first. Two at opposite ends reach the whole space.
- Noise. Rated performance is on the top speed. Two units on medium can match one on high with less noise.
- Backup. When one needs a filter, the other still runs. On a smoky week you can move one to the bedroom at night.
The tradeoff is upkeep. Two units means two sets of filters to replace and two outlets to find.
The picks
- Levoit Vital 200S-P. The strongest unit on this site, with an AHAM Verifide smoke CADR of 250 CFM. Buy one for an open room up to about 390 sq ft. The caveat: it is louder on high than the smaller units, and the app needs 2.4 GHz WiFi.
- Coway Airmega AP-1512HH. A good unit to buy in pairs. Auto mode lets each one idle until its sensor sees particles. The caveat: no app, so you set each one by hand, and the listing we read shows no verified CADR.
Do not do this
Do not put one small purifier in a big room because the box says 1,000 sq ft. A Levoit Core 300 is a fine bedroom unit at about 220 sq ft. In a 600 sq ft great room it changes the air less than twice an hour.
For where to stand them, see where to place an air purifier.
Check any other model with the room size calculator, or see all five picks on the best by room size page.
An air purifier reduces airborne particles. It is not a medical device, and nothing here is medical advice. If anyone in your home has asthma, allergies or another condition, follow your doctor's guidance.