Every air purifier for allergies in this guide has been tested to the exact same standards, using the same processes. We created a series of tests to measure particles of different sizes, to see how each air purifier performs with certain types of impurities. We use a particle counter for all our testing, and our equipment is capable of measuring the smallest pollutants (0.3 microns) that can be removed from the air by a purifier.
We start by running an ambient air quality test, where we run the air purifier in multiple rooms in a home to see how it performs at the regular setting, and the highest possible setting (below 50 decibels). We make note of readings after 15 and 30 minutes to see the speed at which the machine removes particles from the air. We also measure the noise levels generated by the fan, to comment on how noticeable the purifier will be in an average home.
We then test different particle sizes using matches and incense to generate different types of smoke, taking measurements at regular intervals and on different speed settings.
Our testing also takes into account the size of the unit, the cost, ease of use, availability of additional parts, and the energy use on the lowest and highest settings. Finally, we check online user reviews to see what people think, and we test for any persistent problems or defects that we read about.
As per our testing policy, we fully disclose all our findings in our reviews.