Manufacturers rate purifiers for a maximum room size. Matching that rating to your space helps you buy a unit that suits it.
Measure your room
Multiply length by width to get square footage. For rooms with high ceilings, note the ceiling height, since ratings often assume a standard height.
Read the coverage rating
Brands publish a coverage figure in square feet or square metres. AirDoctor, for example, lists coverage ranging from about 305 to 1,043 sq ft across its models on its official site. Always confirm the figure for the exact model.
Consider open layouts
An open-plan space is larger than one room. Add the connected areas, or choose a model rated above the total.
Give yourself headroom
If your room is close to a model's limit, the next size up can be a more comfortable fit.
Check noise and running cost
Larger units can be louder at higher speeds and cost more in electricity and filter replacement. Check these on the official page.
Quick checklist
- What is my room's square footage?
- What is the model's rated coverage?
- Is the layout open?
- What are filter replacement costs?
