IKEA Förnuftig Air Purifier: Cheap, Sleek—and Weak

The super-hyped IKEA Förnuftig air purifier looks great, and it’s quite inexpensive compared with other machines. Unfortunately, our testing proved it to be much less effective than other air purifiers. We don’t recommend it.

What the Förnuftig is—and isn’t

The Förnuftig is a physically small and thin air purifier suitable for placing on the floor, positioning on a table or desk, or hanging on the wall. Its slender footprint saves space, and it’s undeniably attractive, with its tweed-like fabric cover. But it isn’t a true-HEPA purifier, or a very powerful purifier, period. It’s designed to capture PM2.5—that is, particles 2.5 microns in diameter and above, in contrast to the 0.3-micron HEPA standard. That means it’s optimized for larger airborne particles such as pollen and mold spores, rather than for very fine particulates like wildfire smoke, as HEPA filters are. (HEPA filters snag larger particles even more efficiently than they capture very fine ones; PM2.5 filters also capture finer particles, but with lower efficiency.)

An IKEA representative told us that “this is a deliberate design consideration, to find the right balance between affordability, small form factor for high home furnishing appeal and low energy consumption, while retaining a comparably high air flow and CADR.” That’s a perfectly valid approach, and IKEA is very open about the Förnuftig’s limitations—commendable honesty in a category full of overblown claims. But with a clean air delivery rate (CADR) of just 82.4 cubic feet per minute, the Förnuftig is appropriate for only very small rooms, no more than 125 square feet (based on the Association of Home Appliance Manufacturers’s “2/3 Rule”). And IKEA offers an even more conservative suggestion of just 100 square feet, roughly a 10-by-10-foot space. In short, it’s cheap, sleek—and weak. We don’t recommend it. Our pick among small-space purifiers, the Levoit Core 300, is not much more expensive, is a true-HEPA machine, and has a CADR of 135, which means it’s effective in rooms up to 200 square feet.

How we tested

We tested the Förnuftig the same way we test all air purifiers: by generating smoke with wood matches and measuring the percentage of smoke particles it removed over the course of 30 minutes. (You can find full details in the How we tested section in our guide to air purifiers.) For HEPA purifiers, we focus on ultrafine particles at the HEPA-standard 0.3-micron size, and we looked at the Förnuftig’s performance on them, too, so that we could compare its performance, apples to apples, with that of the HEPA filters we’ve tested in the past. But because the Förnuftig is designed to capture PM2.5 (again, 2.5-micron particles), we also measured its performance on 3-micron particles. (Our professional-grade TSI AeroTrak 9306 particle counter separates its measurements into 0.3-, 0.5-, 1-, 3-, 5-, and 10-micron categories.) IKEA believed that the 3-micron category would be the appropriate one for us to measure the Förnuftig’s performance by.

The Förnuftig disappointed, even when we considered that the test room was larger than the machine is meant for: It removed just 85.2% of 3-micron particles in half an hour on high and 73.6% in half an hour on medium. Its performance on 0.3-micron particles was worse: 64.5% removed on high and 53.5% on medium. Compared with the Levoit Core 300, which removed 97.4% and 92.6% of 0.3-micron particles and virtually all 3-micron particles on the same settings, that’s very poor.

No VOC filter included

The Förnuftig can operate with a small VOC filter, but this filter for gas cleaning must be purchased separately. (Most air-purifier makers include VOC filters upon purchase and as part of their replacement-filter sets.) Installing the VOC filter also lowers the machine’s CADR to just 70.6 cubic feet per minute, reducing its effective room size to 106 square feet.

Not good for wildfire smoke

The 2021 fire season has arrived in the American West, creating smoke conditions in many cities and towns. If you’re looking to improve your indoor air quality, a true-HEPA (or equivalent) purifier can make a huge difference—they’re exceptionally good at capturing ultrafine smoke particles, down to at least 0.01 micron in diameter. (This also makes them exceptional at capturing airborne viruses, another lingering worry.)

In our full air purifier guide, we have multiple options for living-room-sized spaces, and a pick for extra-large spaces, along with our bedroom/budget pick, the Levoit Core 300. We think you’ll be able to find a purifier that meets your budget, your needs, and your taste. But the Förnuftig isn’t among them.