Large Open Space: One Large or Many Small Air Cleaners?


Blueair PRO XL Air Purifier

Dear AllergyBuyersClub,

I’m thinking of getting a large air cleaner for my home, but I’m not sure that’s my best option? Should I be looking at getting a few smaller air cleaners? Wouldn’t it be easier to just have one air filter to change, rather then a few? It’d just be nice to be cleaning all the air in my home, so I don’t have watery eyes and to be sneezing all summer long, like I was last summer.

Any advice you could give would be a great help,



Dear Deborah,

A large air purifier, or air cleaner, will work in multiple rooms if they’re fairly open to each other. If one of the rooms has closed doors, a large air purifier won’t work to clean the air in other rooms. If you’re wanting to close doors the only way to clean the air in room would be for it to have its own air cleaner, at least in this case, smaller air cleaner. However, if the door is open the air will circulate into the other room and eventually work its way into the air cleaner. A couple of factors will affect how fast the air is cleaned, one is how large the air cleaner is and how many air change it does per hour. The size of an air purifier is measured in CFM (cubic foot per minute) of air that is drawn into the air purifier, the more circulation you have, the more it will draw the air from the adjoining room that much faster.

Also, as the particulates in the air space are reduced those remaining will equally space themselves apart through dispersion so over time they will work their way toward the opposite side of the air space. The air circulation of the air purifier will reduce the amount of particulates, which will be bring the leftover particles closer to the air cleaner. This process makes it possible for the air on the opposite side of the room to be cleaned.

QuietPure Home Air Purifier
QuietPure Home Air Purifier

Furthermore, the cleaning process in a large area or multiple open rooms is enhanced if there is increased circulation through the use of fans. If you have a fan pulling the air out of an adjacent room it will be easier for this air to be drawn into the air purifier to be cleaned.

As far as your question concerning the large open space and the use of one large air cleaner as opposed to several small air cleaners, the main ingredient is the air changes per hour (ACH). In order to figure out the ACH, you’ll need to take the cubic feet of the air space and divide that into the cubic feet of air that is cleaned by the unit in an hour.

For example, if your room is 125 square feet with an 8 foot ceiling than it is 1000 cubic feet. If you are considering an air cleaner you with 100 CFM and 6 air changes, then it will clean 6000 cubic feet an hour, which should be more than enough.

Acceptable air changes per hour will range from as low as 2 to as high 6. Two to four air exchanges is a good norm to use when measuring your room for the right size unit. In conclusion, several air cleaners positioned throughout your air space would be able to clean the air in the area faster than one large unit even though you still could clean the area with one large unit. This would be especially true if the overall area is subdivided into several small rooms with limited openings. This would reinforce what I said earlier about fans running in the various rooms to help circulate the air. The main thing to consider is that one large unit will take longer and you would need to run it longer and on its highest speed.

If you have any questions concerning any of this please feel free to give us a call.

Thank you,

Dave Barnaby