Right Size Air product guide
PuroAir 400 HEPA Air Purifier
Buyers wanting auto mode and a child lock who accept unpublished CADR
The PuroAir 400 uses one composite filter with an air-quality sensor, auto mode, timer and child lock. PuroAir claims 2,000 square feet an hour but publishes no CADR, and its manual gives both 8-inch and 3-foot clearances. Two-year warranty with registration.
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Published specifications
- PuroAir: up to 2,000 sq ft in an hour; no CADR published
- PuroAir: 14.4 L x 8.1 W x 21.5 H in, 14.7 lb, 80 W
- Manual: auto mode, fan speeds, 2/4/6/8 h timer, child lock
- Manual: >8 in from obstacles; 3 ft from appliances
- Manual: filter not washable; reset hold 10 s
- Manual: two-year warranty with registration
Fit and limits
Strengths
- Auto mode with a sensor that calibrates on power-up
- Timer and child lock
- Manual describes a sensor test at 12 inches
Caveats
- No CADR or verified room size published
- Manual gives conflicting clearance distances
- Humidity can push auto mode to higher speeds
What the PuroAir 400 is
The PuroAir 400 uses a composite filter, and the manual says to use only genuine PuroAir filters. It has an auto mode that calibrates for 10 to 20 seconds after power-on, a choice of fan speeds, a 2, 4, 6 or 8 hour timer and a child lock.
PuroAir lists it at 14.4 inches long, 8.1 wide and 21.5 high, 14.7 pounds and 80 watts. The manual says the filter reset button is held for 10 seconds after a change, and it lists the placement and sensor-test distances covered below.
Coverage claim without a CADR
PuroAir's page and the Amazon title claim coverage up to 2,000 square feet in an hour, which PuroAir says is based on testing in an ISO 17025 lab and ventilation rates. Neither the product page, the manual nor the Amazon table we read gives a CADR figure or mentions AHAM verification.
Without a CADR you cannot work out how many air changes per hour the 400 delivers in a given room, so compare it cautiously with models that publish verified figures. The 2,000 square foot claim is PuroAir's own and we do not restate it as verified.
The manual gives two clearance figures
The manual's placement page says to keep the air intake and output more than 8 inches from any obstacle, to keep the purifier 3 feet from other electrical appliances, and not to share a socket with another appliance. Its troubleshooting table says the inlet and outlet should be not less than 3 feet from obstacles.
A later sensor-test page asks for at least 12 inches around the unit. With three different numbers in one document, the safest plan is to give the 400 as much open space as your room allows and at least 3 feet from other electronics.
Auto mode and humidity
After power-on, the sensor calibrates for 10 to 20 seconds, then auto mode sets the fan from its reading. The manual notes that high indoor humidity can trigger a poor reading, so a damp room may run faster than the air quality warrants.
The manual includes a sensor test performed 12 inches from the unit to check that it responds. The manual's safety pages carry the room and use restrictions, which we did not record in detail, so read them before placing the unit.
Filter and cleaning
The filter is not washable. Replace it when the manual's indicator prompts, then hold the reset button for 10 seconds. The manual's care page describes cleaning the unit; follow it rather than any general advice.
Neither the manual nor the product page we read states a replacement interval in months or hours. PuroAir sells a PuroAir 400 replacement filter and a filter subscription, which the manual ties to its lifetime warranty offer.
Warranty: two years with registration
The manual says PuroAir purifiers bought directly or through an authorised reseller include a two-year warranty with registration, covering defects for two years from purchase. PuroAir's page and the Amazon field both describe a two-year warranty.
A lifetime warranty applies only while a PuroAir filter subscription stays active. The manual's 100-day full-refund guarantee applies to purifiers bought from PuroAir, and detailed terms are on PuroAir's refund policy page, which we did not read.
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Primary sources
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Compare with
- GermGuardian AC4825E 22-inch HEPA PURE Tower Air Purifier with UV-C
A room around 153 sq ft, with a foot of clear space all round
- Coway Airmega Mighty AP-1512HH Air Purifier, Black
A bedroom or office up to about 361 sq ft, with 8 inches clear around it
- Levoit Core 300-P Air Purifier, White
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- Afloia Kilo Air Purifier, White
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- Levoit Vital 200S-P Smart Air Purifier (LAP-V201S-WUS), White
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- Honeywell HPA304 Allergen Plus HEPA Air Purifier, White
Rooms up to about 465 sq ft where simple manual controls suit
Side-by-side pages, this model next to: Levoit Vital 100S-P Smart Air Purifier, White (LAP-V102S-WUS), AirDoctor AD5500 3-Stage UltraHEPA Air Purifier.