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If you're searching for an air purifier because pollen or household dust bothers you, or because you've started noticing pet odor and shed hair since getting a pet, you'll quickly run into a problem: every manufacturer states room coverage and filter type differently, making it hard to tell what size you actually need. Here we compare four products on five points (room coverage, quietness, upkeep, energy use and extra features), using only specs from official and retail pages.
Our Picks — The Right One for You
Daikin MCK706A-W
The widest coverage of the four on the old rating standard (31 tatami mats; 21 under the new one, and the other makers use different standards). Its quietest setting is 18 dB and 10 W, the filter needs no replacement for 10 years, and it works with a smartphone. Also #1 on the Spec Score.
Sharp KC-J50C-H
Covers up to 23 tatami mats of air purifying. Its quietest setting is 20 dB and 3.1 W, and the dust and deodorizing filters are rated for about 10 years.
Iris Ohyama AAP-S30C-W
Its quietest setting is 19 dB and 2 W, lower power than the Sharp (3.1 W) and the Daikin (10 W), with an auto mode. Coverage is smaller at about 16 tatami mats.
Levoit Core P350
- Operating noise24 to 46 dB
- Power consumptionUp to 39 W
Rated for 20 tatami mats, 24 dB on its lowest setting. An activated-carbon filter absorbs odors, and it has a 4-step timer and a child lock. Filter life is 2 years.
Pros and Cons of Air Purifiers
Here's a summary of what tends to satisfy people after buying, and what's worth checking before you do.
Pros
- Reduces bothersome odors and particles like pollen, household dust, and pet smells
- Filtration performance such as a HEPA filter makes it easier to keep your room's air clean
- Choosing one that matches your room's coverage makes it easier to get results suited to your room's size
Cons
- If you're already using a unit suited to your room, the benefit of upgrading is limited
- For very small spaces like an office desk, a compact tabletop type is easier to use
- In a living situation where you don't need an air purifier much, it becomes a lower priority
How to Choose an Air Purifier: 7 Points
Here are 7 points to check before you buy. The figures in the diagrams come from the official and retail-page specs of the products in this article.
Match the Rated Room Size to Your Room
The rated room size shows how comfortably the unit can clean a room of that size. Choose one rated above your actual room, and even a low setting can keep the air moving.
Related pickDaikin MCK706A-W（Room coverage 5/5）
Know the Filter and Deodorizing Methods
Pollen and dust are caught by filters; odors are absorbed by activated carbon or broken down or suppressed by discharge or ions. The products here each combine these differently.
Decide Whether You Need Humidifying
The Sharp and Daikin models here purify and humidify in one unit. That helps if dry air also bothers you, but it adds refilling and upkeep.
Operating Noise (Especially for a Bedroom)
If it will sit in a bedroom, check the noise of its quietest mode. The gap from the top setting also varies a lot by model.
Related pickDaikin MCK706A-W（Quietness 5/5）
Power Consumption (A Guide to Running Costs)
Power use changes a lot with the mode. If you will leave it on, look at the power drawn in the quietest mode.
Related pickIris Ohyama AAP-S30C-W（Energy use 5/5）
Ease of Upkeep and Filter Replacement
How satisfied you are depends on whether you can keep up filter care and replacement. We look at four things.
Extra Features
Auto mode, timer, child lock and other handy extras, in one table.
Related pickDaikin MCK706A-W（Extra features 5/5）
Spec Score Ranking
→ Swipe sideways to see the full table. Use the buttons to re-sort. Click a product name for details. You can also sort by clicking a column heading.
| Rank | Product | Buy (prices as of date shown) | ||||||
|---|---|---|---|---|---|---|---|---|
| 1 | DaikinMCK706A-WHumidifying Streamer air purifier (Twin Streamer + active plasma ion) | 4.30 | 5 | 5 | 3 | 3 | 5 | See on Amazon¥50,769See on Rakuten¥56,400Price as of 2026-09-09 · affiliate link · Opens the shop's site |
| 2 | SharpKC-J50C-HHumidifying air purifier (Plasmacluster 7000) | 4.00 | 4 | 4 | 4 | 4 | 4 | See on Amazon¥24,980See on Rakuten¥32,800Price as of 2026-09-09 · affiliate link · Opens the shop's site |
| 3 | Iris OhyamaAAP-S30C-WAir purifier (3D Nano Charge HEPA, no humidifier) | 3.25 | 2 | 4 | 4 | 5 | 2 | See on Amazon¥11,270See on Rakuten¥11,000Price as of 2026-09-09 · affiliate link · Opens the shop's site |
| 4 | LevoitCore P350Air purifier (cylindrical, 3-layer filter, no humidifier) | 3.00 | 3 | 3 | 3 | – | 3 | See on Amazon¥14,980See on Rakuten¥14,980Price as of 2026-09-09 · affiliate link · Opens the shop's site |
Prices are as of 2026-09-09. They change with sales and stock, so please check the current price on the linked page.
A "–" in the table means the manufacturer and retail pages do not list that item (it is not counted in the score).
What each criterion means, and its weight
Each criterion is scored 1 to 5 and the overall score is the weighted average. The exact thresholds are in How the Spec Score Is Calculated.
- Room coverageweight 30%
- Rated room coverage for air purifying (maximum)
- Quietnessweight 20%
- Operating noise (quietest mode)
- Careweight 20%
- Care (starts at 1 point, +1 for each that applies)
- Energy useweight 15%
- Power consumption (quietest mode)
- Extra featuresweight 15%
- Extra features (starts at 1 point, +1 per listed feature, max 5)
- Overall Spec Score
- Shown only when at least 4 of the 5 criteria have a score; the weighted average is taken over the criteria that do.
Compare 2 to 3 products side by side
Tick "Add to compare" in the table above and the products appear here (up to 3).
Product Notes
Daikin・Humidifying Streamer air purifier (Twin Streamer + active plasma ion)
Daikin MCK706A-W
- Room coverage5/5
- Quietness5/5
- Care3/5
- Energy use3/5
- Extra features5/5
Good forBest for a large living room, with humidifying and odor control in one unit
Good points
- The widest coverage of the four on the old rating standard (31 tatami mats; 21 under the new one, so not directly comparable with the other makers' figures)
- Quiet at 18 dB on its lowest setting (10 W)
- TAFU filter needs no replacement for 10 years, plus smartphone control and a child lock
Things to note
- A large, heavy unit (W315 × D315 × H760 mm, about 12.5 kg)
- Its top setting is 54 dB and 82 to 84 W, a big gap from the quiet modes
Sharp・Humidifying air purifier (Plasmacluster 7000)
Sharp KC-J50C-H
- Room coverage4/5
- Quietness4/5
- Care4/5
- Energy use4/5
- Extra features4/5
Good forBest for handling humidifying and air purification quietly in one unit
Good points
- Rated for 23 tatami mats of air purification (humidifying: 8.5 wood-frame / 14 prefab)
- Quiet and low-power at its lowest setting: 20 dB and 3.1 W
- Dust and deodorizing filters are rated for replacement about every 10 years
Things to note
- Its top setting is 52 dB and 54 W, a big gap from the quiet mode
- When humidifying, you must refill the tank and care for the humidifying filter and tray
Iris Ohyama・Air purifier (3D Nano Charge HEPA, no humidifier)
Iris Ohyama AAP-S30C-W
- Room coverage2/5
- Quietness4/5
- Care4/5
- Energy use5/5
- Extra features2/5
Good forBest for a quiet, affordable unit in a bedroom or single room
Good points
- 19 dB and 2 W on its lowest setting: quiet, and lower power than the Sharp (3.1 W) and Daikin (10 W)
- Senses dirt and odor and adjusts the fan automatically
- Light at about 2.5 kg, and the lowest price of the four as listed (2026-09-09)
Things to note
- Rated coverage is about 16 tatami mats (High), on the smaller side
- Filter life is 2 years (per Kakaku.com), so budget for replacements
Levoit・Air purifier (cylindrical, 3-layer filter, no humidifier)
Levoit Core P350
- Room coverage3/5
- Quietness3/5
- Care3/5
- Extra features3/5
Good forBest for pet odor and shed hair in a bedroom or single room
Good points
- Rated for 20 tatami mats; cleans an 8-tatami room in about 13 minutes (maker's claim)
- Quiet at 24 dB on its lowest setting, with a 4-step timer and a child lock
- Activated-carbon filter absorbs odors; no humidifier means no water upkeep
Things to note
- Filter life is 2 years, with a recommended replacement every 6 to 12 months (Amazon listing)
- Its top setting is 46 dB and up to 39 W, a big gap from the quiet mode
Who Air Purifiers Are a Good Fit For — and Who Should Consider Other Options
As a category, air purifiers tend to work well for the following people.
Good fit if you...
- Are bothered by pollen, household dust or pet odor
- Are looking for a model whose room coverage matches the size of your room
- Want to know the filter replacement effort and cost up front, before choosing
Consider other options if you...
- Already have an air purifier sized to your room and are happy with it
- Only need to cover a very small area, such as an office desk (a desktop model is easier to handle)
- Care more about a low purchase price than about combined humidifying and deodorizing functions
Common Concerns and How to Handle Them
With air purifiers in general, operating noise can turn out louder than expected, and filter replacement costs can add up. If the noise bothers you at bedtime, setting the fan to auto or quiet mode, and choosing a model rated well beyond your room's size, makes it easier to keep the air moving even on a low setting. Filter replacement frequency and cost vary a lot by model, so checking the approximate price and replacement cycle of genuine filters before you buy helps avoid a surprise in running costs later. Dust buildup at the air intake can reduce purification, so it's worth vacuuming or wiping it with a dry cloth about once a month.
How the Spec Score Is Calculated
Each criterion is scored from 1 to 5, and the overall score is the weighted average. We use the manufacturer's official figures; where the official site could not be read, we fill in from Amazon, Rakuten Ichiba, Kakaku.com and similar retail or comparison pages (only pages that match the exact model number). A criterion with no published figure is left out and the average is taken over the rest (for care and features, only items that are actually listed earn points).
| Room coverage (30% weight) | Rated room coverage for air purifying (maximum) 30 tatami mats or more = 5 / 22 or more = 4 / 18 or more = 3 / 14 or more = 2 / below = 1 (figures as each maker states them; Daikin's is the old standard) |
|---|---|
| Quietness (20% weight) | Operating noise (quietest mode) 18 dB or less = 5 / 20 dB or less = 4 / 24 dB or less = 3 / 30 dB or less = 2 / above = 1 |
| Care (20% weight) | Care (starts at 1 point, +1 for each that applies) (1) filter replacement rated at 5+ years (2) no humidifier, so no water upkeep (3) pre-filter can be vacuumed (4) a lamp signals care or replacement |
| Energy use (15% weight) | Power consumption (quietest mode) 3 W or less = 5 / 5 W or less = 4 / 10 W or less = 3 / 20 W or less = 2 / above = 1 |
| Extra features (15% weight) | Extra features (starts at 1 point, +1 per listed feature, max 5) Auto mode / timer / child lock / smartphone or smart-speaker control / humidifying / ion or Streamer-type purifying |
Summary
This comparison uses published specs, not hands-on impressions. Decide first on the size of your room, whether you want humidifying in the same unit, and whether it will go in a bedroom, then choose.
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Update history
Show update history (2)
- Rewritten on the new template (Spec Score, product detail pages).
- Display improvements (summary at the top, ranking cards, sortable comparison table with side-by-side compare, in-page navigation). Scores, prices and links are unchanged.