Basements can be challenging environments for household air purifiers to operate in. They tend to be fairly large, so something that provides a high clean air delivery rate (CADR) is required. Beyond that, an air purifier in a basement will need to contend with dust, pet dander, and, in worst-case scenarios, mold spores; thankfully, these particles trend on the larger side, and most units with HEPA-grade or near HEPA-grade filtration systems will be up to the task. If you don't want to have to go into your basement and fiddle with settings every now and then, particle sensors and an automatic fan speed adjustment feature are nice added touches that can make for a more pleasant user experience.
We've tested over 40 air purifiers, and below are the best air purifiers for basements that we've tested. If you want a broader overview of the product landscape, check out our recommendations for the best air purifiers, the best air purifiers for large spaces, and the best air purifiers for mold.
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Best Air Purifier For Basements
Particle Filtration Rate9.1Measured PM1.0 CADR729 m³/hr (429 CFM)Recommended Room Size @ Max Fan Speed62.2 m² (670 ft²)Measured PM1.0 CADR361 m³/hr (213 CFM)See all our test resultsRecommended Room Size30.8 m² (332 ft²)The Blueair Blue Signature Large is the best air purifier for basements that we've tested, thanks to its remarkably high clean air delivery rate and easy-to-live-with design. Its multi-stage filtration system consists of a pre-filter for trapping dust clumps and fine fur, a particle filter for removing smaller airborne irritants like mold and pet dander, and activated carbon and mineral layers for reducing odors. It also has a particle-ionization system that draws particles to its electrostatically charged filter layer, further improving filtration performance. That said, like most ionizer systems, it also produces ozone, a respiratory irritant. Its ozone production rate is AHAM-certified to fall within safe limits, but this system can't be disabled and could represent a potential dealbreaker for those who are particularly sensitive to ozone.
In terms of performance, this high-end model is among the best household units we've tested, with a high enough max clean air delivery rate (CADR) to operate effectively in the largest basements. Performance does drop slightly at lower, quieter fan speeds, which is something to be aware of if you have it running while watching TV as it runs, but even in a low-noise configuration, it provides sufficient performance for most dens. The Blueair is Wi-Fi enabled, too, so you can change settings or monitor air quality in your basement without actually going down there, thanks to its laser particle sensor.
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Best Mid-Range Air Purifier For Basements
Particle Filtration Rate8.8Measured PM1.0 CADR617 m³/hr (363 CFM)Recommended Room Size @ Max Fan Speed52.7 m² (567 ft²)Measured PM1.0 CADR275 m³/hr (162 CFM)See all our test resultsRecommended Room Size23.5 m² (253 ft²)For those who consider the Blueair Blue Signature Large's always-on ionizer a dealbreaker but still want something that performs well in larger dens, consider the Levoit Core 600S. While the Levoit's max CADR is impressively high, and generally sufficient for bigger basements, it still lags behind the Blueair in this respect; while the latter is effective in spaces over 650 ft2 (60.4 m2), the Levoit is recommended for use in rooms up to nearly 570 ft2 (53.0 m2). As mentioned earlier, it lacks an ionization system and instead uses a conventional three-stage mechanical filtration system, which is still more than up to the task of handling airborne dust and mold.
The Levoit is Wi-Fi enabled, allowing you to pair the device with your smartphone to view air quality estimates, adjust the fan speed, and receive filter change alerts through the VeSync companion app. Beyond that, the 600S also features Google Assistant and Amazon Alexa integration, so you can control it using voice commands. It runs a little louder at both its maximum and minimum fan speeds than the Blueair, though it'll still be masked by a nearby TV playing at a normal volume. It does have a slightly narrower footprint, though it can't be used as an end table.
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Best Budget Air Purifier For Basements
Particle Filtration Rate8.0Measured PM1.0 CADR424 m³/hr (250 CFM)Recommended Room Size @ Max Fan Speed36.2 m² (390 ft²)Measured PM1.0 CADR159 m³/hr (94 CFM)See all our test resultsRecommended Room Size13.6 m² (146 ft²)If you don't need the large-room performance of the Levoit Core 600S and would prefer something a little cheaper, consider the Winix C610. At its highest fan speed setting, it can consistently capture airborne pollutants in areas up to approximately 400 ft² (37.2 m²), making it a good option for medium-sized basements. Like the Levoit, this unit features a three-stage filtration system with a pre-filter for longer hair strands, a True HEPA filter for fine dust and mold spores, and a carbon filter to eliminate odors. However, it also features the brand's PlasmaWave technology, which is meant to neutralize fine airborne pollutants rather than cause them to clump together. This system produces a small amount of ozone while running, which Winix claims to fall well below harmful levels. Still, if you or someone in your home is particularly sensitive to ozone, you can disable this ionization system, unlike the Blueair Blue Signature Large. It's also worth noting that turning it off has very little impact on overall air cleaning performance.
There's a good array of extra features, too: you can set the unit to automatically adjust its fan speed, so you don't have to worry if air quality drops while you're asleep. You can also operate the air purifier remotely and set operating schedules with the smartphone app.
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Best Air Purifier For Small Basements
Particle Filtration Rate7.0Measured PM1.0 CADR255 m³/hr (150 CFM)Recommended Room Size @ Max Fan Speed21.8 m² (234 ft²)Measured PM1.0 CADR99 m³/hr (59 CFM)See all our test resultsRecommended Room Size8.5 m² (91 ft²)For those with smaller basements who only require something compact, the Blueair Blue Pure 511i Max is worth a look. This compact unit doesn't offer the same level of performance as even the relatively affordable Winix C610, as it'll take over 30% longer to achieve a similar level of air quality in an equivalently sized space at its highest fan speed. That said, it's also considerably more compact than the already decently small Winix, and you can set it up on a coffee table or bookshelf with room to spare. It's also exceptionally quiet, especially at its lowest fan speed, though it's worth noting that its performance degrades significantly in that configuration, to the point where it'd be only suitable for a crawl space.
Despite the significant gulf in capability, the 511i Max uses a similar filter configuration to the bigger and pricier Blueair Blue Signature Large, with a three-stage mechanical filter system and an additional particle ionization system, which, unfortunately, can't be disabled. If you or someone in your household suffers from serious ozone sensitivity and you consider that a dealbreaker, look at something like the PuroAir 240, though its particle filtration rate does lag behind that of the Blueair.
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Best DIY Air Purifier For Basements
Particle Filtration Rate9.5Measured PM1.0 CADR943 m³/hr (555 CFM)Recommended Room Size @ Max Fan Speed80.5 m² (867 ft²)Measured PM1.0 CADR636 m³/hr (375 CFM)See all our test resultsRecommended Room Size54.3 m² (585 ft²)If you're working on your basement or simply have an unfinished den and would like something that can keep dust and mold to a minimum, consider building your own Corsi-Rosenthal Box. We built our own by following this guide, which uses four 3M Filtrete air filter sets and a Lasko 20-inch box fan. This homemade option lacks the quality-of-life features of devices like the Blueair Blue Signature Large, with no particle sensor, Wi-Fi connectivity, or odor-absorbing carbon filter. Since you'll need to dispose of the filters at the end of their useful life, which can be as little as three months, this also incurs a higher long-term financial investment. A box fan is also quite loud while running, and it will be a nuisance if you use it in an area where you regularly entertain guests or simply relax to watch TV. It's worth pointing out that newer iterations of this design use multiple compact PC cooling fans instead to reduce noise (not to mention power consumption). However, we haven't built such a unit and can't verify if it'll perform similarly.
So, with all those caveats, why bother building a Corsi-Rosenthal Box? Well, even a basic unit such as this provides a higher clean air delivery rate than the majority of mass-market options, including the already exceptionally well-performing Blueair, and a full-sized Corsi-Rosenthal Box is over 20% faster to achieve the same level of air quality in an equivalently-sized room. This makes it ideal for larger basements and a stellar fit if you aren't concerned about aesthetics or operating noise.
Notable Mentions
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Blueair Blue Pure 211i Max:
The Blueair Blue Pure 211i Max is a high-end air purifier that delivers comparable overall performance to the Blueair Blue Signature Large, though with a more conventional aesthetic. It's a good alternative if you can find it for a lower price, just know that it's noisier.
See our review -
Coway Airmega 400:
The Coway Airmega 400 is a high-end air purifier that offers similar performance to the Blueair Blue Signature Large at its highest fan speed. That said, it's also noisier and doesn't perform as well at lower fan speeds.
See our review -
NuWave OxyPure:
The NuWave OxyPure is a high-end air purifier with a unique washable filtration system that can help lower recurring costs compared to alternatives like the Blueair Blue Signature Large. That said, the Blueair performs better, runs quieter, and takes up less room.
See our review -
Corsi-Rosenthal Box with Single Filter:
If you only have a smaller unfinished basement with lower CADR needs and don't want to go through the hassle or expense of sourcing another quartet of furnace filters, consider building a Corsi-Rosenthal Box with Single Filter, which also takes up less room than a conventional Corsi-Rosenthal Box.
See our review
All Reviews
The recommendations above are among the best air purifiers for basements for most people. We factor in price, visitor feedback, and availability.
That said, there's no single best option that will suit everybody; your choice will depend on your budget, the size of your basement, your tolerance for operating noise, and whether you prefer a device with convenience features like Wi-Fi connectivity. If you'd like to choose for yourself, here's the list of all our air purifier reviews, ranked by their clean air delivery rate.