“Where should I place my air purifier” is a common question people have when getting an air purifier. Does an air purifier’s position affect its performance? Is it best to put an air purifier next to a wall? This post provides a data-backed answer on how to best place your air purifier in your home, classroom, or office space.
1. Best Place to Put an Air Purifier: Distance From Wall
For purifiers to work best, they need room to take in the air and push it out to the room. If it’s backed up against the wall, it can’t take in as much air.
So how far from the wall should the purifier be? I decided to put our purifiers to the test. Here’s how:
When the purifier was flat against the wall, the airflow was only about 5%! Moving the air purifier 4 cm from the wall increased the airflow from 5% to 94%. At 10 cm from the wall, airflow was back up to 100% of its normal value.
Keep Your Purifier an iPhone’s Length from the Wall
Since not all air purifiers have exactly the same inlet, a safe bet would be to keep your air purifier inlet at least 15 cm from the wall. 15cm (or just under 6 inches) is the same as the height of an iPhone 11. You can use it (or a similar phone) to make sure your purifier is best placed away from a wall.
Is it better to sleep next to your air purifier? Does the location of the air purifier in your room matter? To find out, Smart Air did seven overnight tests to see if the air closer to the air purifier is cleaner than other spots in the room.
2. Best Place for an Air Purifier: Location in Room
Does the location of an air purifier in a room matter? Is it better to place the purifier in a location closer to you? We often get asked by schools “where should an air purifier be placed in a classroom?”
To find out, the Smart Air team placed three Dylos DC1700 pollution particle counters in different spots (and heights) in a room. Then a Smart Air DIY Cannon air purifier was turned on at night, and particle counters tracked the pollution levels throughout the night. The particle counters took turns in each location over the course of multiple nights to account for any variations that might exist between the counters.
In the 15 m2 room, the table was closest to the air purifier, while the sofa was the furthest. Would the location closest to the air purifier have the cleanest air? If so, this could confirm that it is best to put an air purifier as close to you as possible.
Differences between locations were TINY. Here’s how much effectiveness deviated from the overall average across the locations:
You can see how similar the decreases were in this sample test on one particular day. Although there’s a little bit of difference at the beginning, the three lines track each other closely.
The table, which was closest to the air purifier, had only slightly better air quality compared to the other locations.
If we look at the percentage reductions in particles, the differences between locations were less than 1%.
Smart Air ran the tests in a 15m2 bedroom with the doors and windows closed. The DIY Cannon air purifier was strong enough for the size of the room. Finding the right air purifier with enough power (CADR) for your room size is more important than the position of the purifier. In addition, if you sleep with the air purifier on low, make sure the low setting CADR is enough for your room size.
As always, I’m making the data and more info on the test methods openly available for all you fellow clean air nerds. You can download the test data here.
P.S. What About Big Spaces?
Of course, results might be different in big rooms, like a big open office. If you want to see results for a bigger area, check out this test I ran with a single purifier cleaning an entire Beijing apartment.
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Smart Air provides empirically backed, no-nonsense purifiers and masks, that remove the same particles as the big companies for a fraction of the cost. Only corporations benefit when clean air is a luxury.