PuroAir 400 HEPA Air Purifier
PuroAir's largest unit, rated to 2,000 sq ft with a three-stage HEPA and carbon filter, for an open-plan floor rather than a single room.
The 400 is the one to buy if the room is actually big. PuroAir rates it to 2,000 sq ft against the 240's 1,000, and it is the only unit in the line built for an open-plan floor.
Price: $279.99–$977 · Verified: 2026-08-17
The 400 is the one to buy if the room is actually big. PuroAir rates it to 2,000 sq ft against the 240's 1,000, and it is the only unit in the line built for an open-plan floor.
The PuroAir 400 is the top of the line, and the reason to choose it over the cheaper 240 is coverage. PuroAir rates it to 2,000 sq ft per hour against 1,000 for the 240, on a three-stage stack: a pre-screen for hair and large debris, a HEPA layer for particulate, and activated carbon for odors and VOCs. It filters PM1, PM2.5 and PM10 down to 0.1 micron. An air-quality sensor drives an auto mode that steps the fan up on its own, and a light tells you when the filter is due.
The numbers that matter for living with it: 31 dB at the lowest fan speed, 80W, and 14.7 lbs in a 14.4 by 8.1 by 21.5 inch tower. That is louder and heavier than the 130i, which is the trade for the airflow. Warranty is two years, extended to lifetime only while a filter subscription stays active, which is the same lever that drops the purchase price from $324.99 to $279.99.
The same honest caveat that applies to the 240 applies here, because it is a brand-level question rather than a model-level one: independent testing houses including HouseFresh have argued PuroAir's real-world clean-air delivery trails the measured leaders once room size and run time are accounted for. PuroAir does not publish a CADR figure or a HEPA grade for this unit, and we are not going to infer either. Treat 2,000 sq ft as a best-case ceiling, size up rather than down, and run a higher fan speed in a genuinely large space.
An open-plan main floor, a large family room, or a shared space where one unit has to cover more ground than a bedroom purifier can, and where price still matters more than independently-measured top-tier performance.
You want a published CADR, a stated HEPA grade, or independently-verified best-in-class clearance. Coway Airmega, Blueair and IQAir all publish more and test better. Also skip if the room is under 600 sq ft, where the 130i costs less than half and runs quieter.
Where this fits
PuroAir PuroAir 400 cross-shops across several editorial surfaces on this site: the full brand catalog and the in-depth guides for its category.
PuroAir PuroAir 400 - buyer FAQ
How is the PuroAir 400 different from the 240?
Coverage and size. PuroAir rates the 400 to 2,000 sq ft per hour and the 240 to 1,000. The 400 is also physically bigger at 14.7 lbs and 21.5 inches tall, draws 80W, and bottoms out at 31 dB. The 240 is the bedroom and office pick; the 400 is for an open-plan floor. Both run the same three-stage pre-screen, HEPA and activated-carbon stack.
What does it actually cost?
Standalone the 1-pack is $324.99 against a $349.99 compare-at price, verified 2026-08-17. Committing to an active filter subscription drops it to $279.99 and extends the warranty from two years to lifetime, so the subscription is doing real work in both the price and the coverage. Multi-packs run $505 for two and $977 for four.
Does PuroAir publish a CADR rating?
Not for this model. The product page lists room coverage of up to 2,000 sq ft per hour, particulate down to 0.1 micron, and the filter stack, but no clean air delivery rate and no HEPA grade such as H13 or H14. We report what the brand publishes and do not infer the rest. If a published CADR is a requirement, Coway, Blueair and IQAir all provide one.
Is it quiet enough to sleep next to?
At 31 dB on its lowest setting it is quiet, but it is louder than the 130i at 27 dB and it is a much larger machine. For a bedroom specifically the 130i is the better fit and costs less than half. The 400 makes sense where the space is too big for a small unit to keep up.