How to choose an air purifier for a Perth home
Three things matter, in this order: enough clean air for the size of the room, a genuine HEPA filter, and a real carbon stage if smoke is the worry. Here's how to check each one without taking the box's word for it.
How much purifier does your room need?
Measure the room, pick what you're dealing with, and we'll work out the clean air it needs each hour and which units on our list can deliver it.
Where a unit has a tested or published CADR we use it directly. For units without one, we scale our own realistic-room estimate to your ceiling and air-change rate, and say so. How we work out room sizes.
Six things to check
Ignore the headline coverage
Nearly every brand quotes coverage at one air change an hour, which is close to useless for smoke or pollen. You want four or five. As a rule of thumb, take the square-metre figure on the box and divide it by four. Or skip the guesswork and use the calculator above.
CADR is the speed number
Clean air delivery rate, in cubic metres an hour, tells you how quickly a unit actually cleans the air. It's the figure worth comparing between models. Be wary of anything over $300 that won't publish one.
H13 or H14?
An H13 filter captures at least 99.95% of the particles it's tested against and suits most homes. H14, at 99.995%, is worth the step up if you have asthma or react badly to grass pollen. Watch for vague wording like “HEPA-type” or “HEPA-style”, which promises no grade at all.
Carbon is what handles smoke
HEPA catches particles. Only an activated-carbon stage does anything about smoke smell and gases. For Perth's fire and burn-off seasons, carbon isn't optional, and a thin carbon-dusted sheet won't do much. Heavier is better.
Cost the filters, not just the unit
Replacement filters are the real running cost, from about $65 to $130 a year on our list. Over three years a cheap unit with dear filters can cost more than a better one. The running-cost calculator does the sums.
Buy in winter
Prices tend to be lowest from May to July, when nobody's thinking about smoke. Buy then and you're set up before pollen and burn-off season in September and October.
Getting the most out of it
A well-placed mid-range unit will outperform a dearer one stuck in a corner of the hallway.
Put it where you are
Usually the bedroom overnight and the living area by day. One unit moved between rooms beats one left somewhere nobody sits.
Give it room to breathe
Keep the intake and outlet clear: out of corners, off the carpet's edge, and away from curtains and furniture.
Close the door
A purifier cleans a room, not a house. With every door open it's trying to clean the whole place and doing none of it well.
Leave it running
Run it on auto, or steadily on a medium speed, and turn it up on smoke days. Switching on only when you smell smoke leaves it playing catch-up.
Vacuum the pre-filter
In summer, Perth dust clogs a pre-filter quickly. A monthly once-over with a brush attachment keeps airflow up and the main filter lasting longer.
Keep a spare filter
Filters can sell out when a big fire hits. Having one in the cupboard before December is cheap insurance.