Compare an air purifier’s particle CADR with your actual room, then check the fan setting, filter requirements and exact model. A large advertised coverage area without an air-change rate is not enough to compare two machines.
This is a manufacturer-document research guide, checked September 4, 2026—not a hands-on review. We have not measured these units’ cleaning performance, sound, energy consumption or effects on symptoms. There are no editorial star ratings or live price rankings. Product specifications below are attributed to their sources, and gaps are left visible rather than filled with estimates.
A portable cleaner is one part of an indoor-air plan, not a replacement for addressing pollutant sources and appropriate ventilation. EPA describes portable units as serving a room or area and notes that filtration does not remove every pollutant. This guide compares equipment; it does not recommend a treatment for allergies, asthma or another medical condition. EPA overview of home air cleaners.
Affiliate disclosure: Amazon links are affiliate search links. As an Amazon Associate, FindPicked earns from qualifying purchases. Results may contain replacement filters, different regional models or third-party sellers. Check the exact model number and package contents; the manufacturer source links below are available regardless of whether you use an affiliate link.
What the comparison numbers mean
- CADR is clean air delivery rate for particles, commonly expressed in cubic feet per minute (CFM). It is not the same thing as a fan’s raw airflow or a measurement of gas removal.
- Room coverage needs a stated air-change rate and ceiling assumption. One air change per hour and approximately five changes per hour describe very different sizing conditions.
- Published maximum performance does not imply the same performance at a low-noise setting.
- Filter efficiency describes a filter or test condition, not a guarantee that all air in an occupied room has passed through it.
EPA’s selection guide explains these distinctions and provides a room-area/CADR estimation chart based on an 8-foot ceiling. It also explains that gas filtration is a different comparison from particle CADR. EPA portable-cleaner selection guide.
Source-checked model comparison
There is no universal winner here. These are five model families from our existing guide, retained with corrected specifications and clearer limits. Regions and model suffixes matter.
| Model / source | Particle CADR reported by source | Room-size basis or comparison gap | What to check next |
|---|---|---|---|
| Coway Airmega 400, US page | Smoke 328; dust 328; pollen 400 CFM | 1,560 ft² at 2 ACH; 3,120 ft² at 1 ACH | Exact 400 versus 400S; replacement filter set |
| Levoit Core 400S-P, US page | 231 CFM; source lists one CADR number | 358 ft² at 4.8 ACH; 1,718 ft² at 1 ACH | Current model label, filter and intended operating speed |
| Honeywell HPA300, manufacturer technical sheet | Smoke 300; dust 320; pollen 300 CFM | Source specifies 465 ft², up to 5 ACH, ceiling 8 ft or less, maximum setting | Exact HPA300 series and filter quantities |
| Dyson Big+Quiet Formaldehyde BP03 | Comparable smoke/dust/pollen CADR not established from the source used here | Airflow/projection specifications are not substituted for CADR | Exact BP03 variant and published test basis |
| Blueair Blue 3210, Philippines page | No usable CADR table in the source checked | Regional page has ambiguous room-area wording, so coverage is not reproduced | Local manual, model number and replacement filter availability |
Sources: Coway Airmega 400 specifications, Levoit Core 400S-P specifications, Honeywell HPA300 technical sheet, page 2, Dyson BP03 technical sheet, Blueair Blue 3210 regional product page.
Source dates are not test dates: the Honeywell sheet is dated April 2021 and the Dyson sheet November 2023. They were accessible during this review, but a current seller’s model must still match the document. We do not label older technical documentation as a new 2026 performance test.
Worked example: why the larger coverage number can mislead
Consider a synthetic rectangular room measuring 15 × 20 feet with an 8-foot ceiling:
- Floor area = 15 × 20 = 300 ft².
- Volume = 300 × 8 = 2,400 ft³.
- For a hypothetical 200 CFM of particle-cleaned air, equivalent clean-air changes per hour = 200 × 60 ÷ 2,400 = 5.
Now give the same room a 10-foot ceiling. Its volume becomes 3,000 ft³. With the same hypothetical 200 CFM, the arithmetic becomes 200 × 60 ÷ 3,000 = 4.
This is a unit calculation, not a measured result, a target for medical protection or a claim about any listed unit. It assumes the stated clean-air rate is actually delivered and does not model doors, furnishings, changing sources or room mixing. It shows why floor area alone hides an important assumption.
| Synthetic input | 8 ft ceiling | 10 ft ceiling |
|---|---|---|
| Room floor area | 300 ft² | 300 ft² |
| Room volume | 2,400 ft³ | 3,000 ft³ |
| Assumed clean-air rate | 200 CFM | 200 CFM |
| Calculated equivalent changes per hour | 5 | 4 |
To compare real products, use the same units and the source’s stated basis. Do not put a 1-ACH area from one listing next to a 4.8-ACH area from another and call the larger number “more powerful.” For connected rooms, record the actual area to be served instead of using only the patch of floor beside the machine. Use the unit converter when your measurements and the product listing use different units.
Model notes and unresolved questions
Coway Airmega 400: distinguish the model and coverage rate
The current US page identifies the 400 as not Wi-Fi or app-enabled. It lists two pre-filters and two Max2 filters. Its 1,560 ft² area is explicitly at two air changes per hour; it is not directly equivalent to another product’s approximately five-change area. The CADR numbers in the table replace the unsupported 350/400/450 figures in our earlier copy. Coway’s model and filter details.
Investigate if: its documented specifications fit your measured space and operating plan. Resolve before purchase: 400 versus 400S, the complete replacement set and maintenance access. We have not measured this unit in a room.
Search Amazon for the Airmega 400.
Levoit Core 400S-P: avoid merging old and regional specifications
The current US page lists 231 CFM and explicitly pairs 358 ft² with 4.8 ACH. It also lists app control. This guide does not carry forward the old blanket 260 CFM figure or add a filter-grade label absent from the current specification used here. Levoit’s current US model page.
Investigate if: the source-stated performance and control options meet your comparison criteria. Resolve before purchase: the model suffix, local voltage, replacement-filter identifier and performance at the speed you intend to use. A similarly named model in another market is not automatically the same configuration.
Honeywell HPA300: keep the test conditions attached
The manufacturer sheet provides separate smoke, dust and pollen CADRs and identifies the maximum fan setting for its room-size statement. That is more useful than a detached “large-room” label, but the sheet is older documentation rather than a fresh comparative test. Honeywell’s technical sheet.
Investigate if: the documented specification matches your room comparison. Resolve before purchase: the exact HPA300-series unit and the number of HEPA filters and pre-filters required. The manufacturer’s Allergen Plus support page links the relevant manuals; follow the applicable replacement and cleaning instructions rather than washing a filter by assumption.
Dyson Big+Quiet Formaldehyde BP03: leave the comparison gap visible
The BP03 technical sheet describes HEPA, carbon and catalytic filtration components and reports airflow rather than a comparable smoke/dust/pollen CADR table. Those are different measurements. We have not converted its airflow or projection distance into a room-cleaning score or independently validated its gas-removal claims. Dyson’s BP03 specification sheet.
Investigate if: its particular design and documented functions interest you. Resolve before purchase: the exact variant, current filter schedule and comparable performance information for your intended use. A “quiet” product name is not our independent acoustic finding.
Search Amazon for Big Quiet Formaldehyde.
Blueair Blue 3210: verify the local documentation first
The regional page supports a compact footprint of 425 × 200 × 200 mm, but its room-area wording is ambiguous. Rather than silently correcting that wording or borrowing numbers from another Blue model, this guide leaves coverage and CADR unverified. Blue 3210 regional specifications.
Investigate if: you are evaluating this identifiable older/regional model. Resolve before purchase: a local manual with unambiguous performance data, electrical compatibility and available replacement filters. A filter or successor model appearing in a search result should not be mistaken for the same unit.
Make a running-cost comparison you can update
Use a dated worksheet instead of a guessed annual filter price. Record:
- The exact compatible filter identifier and how many pieces make a complete change.
- A current delivered quote for that complete set.
- The manufacturer’s replacement guidance and any conditions or indicator-based instructions.
- Your assumed operating hours and a power figure appropriate to the setting—not an unrelated standby number.
- Whether you can access and maintain the filters where the unit will stand.
An illustrative electricity calculation is watts ÷ 1,000 × hours used = kWh. Multiply by your own electricity tariff if you want a cost estimate. Label an estimate based on maximum rated power as such; it is not a measurement of typical consumption. Filter life also depends on use and conditions, so do not treat an advertised interval as a guaranteed annual expense.
FAQ
Is the highest HEPA percentage the best buying criterion?
Not on its own. Compare the amount of particle-cleaned air delivered to the room as well as the filter specification. A filter-media claim is not a whole-room outcome.
Does a large CADR mean strong gas removal?
No. Particle CADR and gas filtration are different measures. Check the specific gas-filter information and its test conditions instead of inferring gas performance from a particle number.
Can one portable unit serve every room?
Do not assume that from a large area claim. Record the area, ceiling height, layout and manufacturer’s basis. A closed bedroom and a connected living area are different comparison problems.
Why remove the old rankings and prices?
They implied a comparative test and current market pricing that this guide did not substantiate. The replacement is a source-linked decision process with concrete calculations, exact model distinctions and visible unknowns. Product selection is easier to audit when an unanswered question remains a question.