The four things we score
Clean-air speed
CADR, the clean air delivery rate, with independent test results preferred over the maker's figure. It carries the most weight, because it decides how quickly a room actually clears.
Filtration
A genuine, stated HEPA grade (H13 or H14), and a real activated-carbon stage for smoke rather than a thin token layer.
Running cost
Filter price and lifespan at Australian prices, plus power use. We look at the cost over three years, not the sticker price.
Perth fit
How it copes with smoke season and dust: a washable pre-filter, a sensor that reacts to smoke, local filter supply, and noise if it's going in a bedroom.
What the scores mean
| Score | What it means |
|---|---|
| 4.5 to 5 | Buy it. The best in its class for Perth homes. |
| 4.0 to 4.4 | Good in the right room, with a caveat worth knowing. |
| 3.5 to 3.9 | Does the job, but there's better value elsewhere. |
| Below 3.5 | Hard to recommend as a purifier at its price. |
How we work out realistic room sizes
Brands usually quote coverage at one air change an hour. That's enough to slowly freshen a room, not to keep smoke or pollen down. We assume a 2.4 metre ceiling and three and a half to four air changes an hour:
Realistic room (m²) = CADR (m³/h) ÷ (2.4 m × 3.5 to 4)For example, the Levoit Core 400S has a tested CADR of about 340 m³/h. 340 ÷ (2.4 × 4) is 35 m², and 340 ÷ (2.4 × 3.5) is 40 m², so we list it at 35 to 40 m².
For units without a published CADR, our figure is an estimate based on independent test results where they exist, and the comparison table says “Not published” so you know. If your ceiling is higher or you want more air changes for smoke, the room-size calculator redoes the sum for your room.
Prices
Prices are in AUD, checked at Australian retailers and dated; the current set was checked in August 2026. They move often, so treat them as a guide and confirm before you buy. Where a unit is regularly discounted we show the typical sale price and note the list price. Amazon's rules don't let sites display its prices, so Amazon buttons show only the retailer's name.
Sources we rely on
- HouseFresh: independent bench testing of the Levoit, Winix and Dyson units, including measured CADR and running costs. Levoit Core 400S, Winix range, Dyson.
- CHOICE: expert testing of purifiers sold in Australia, including the Breville range. Full scores are for members only.
- Manufacturer specifications: Breville, Levoit, Winix, Coway, Philips and Dyson product pages for CADR, filter grade and RRP.
- Air-quality data: the WA Department of Water and Environmental Regulation monitoring network, via the World Air Quality Index project, and the national air quality standards.
- Health research: listed in full at the end of our bushfire smoke and indoor air guides.
Changelog
- Site rebuilt as separate pages. Added guides to bushfire smoke and indoor air, a room-size calculator, a running-cost calculator and a sortable comparison table. The live air-quality reading now comes directly from WA's DWER monitoring stations. Philips 2000i realistic room size revised from 45 to 55 m² to 40 to 45 m² to match our formula. Removed several statistics we couldn't trace to a primary source.
- Prices checked at Australian retailers.