Air purifier size calculator
Enter your room and the problem. We'll show the clean-air rate you need and which units can deliver it.
How it works
A purifier needs to clean all the air in a room several times an hour. We multiply the room's volume by the number of air changes your problem needs:
- Everyday dust: 3 changes an hour.
- Pollen and allergies: 4 an hour.
- Smoke or asthma: 5 an hour.
That gives the clean air delivery rate (CADR) you need, in cubic metres an hour. For units without a published CADR, we use our own estimate, based on lab results where they exist.
Tips
- Measure open-plan areas as one space. Air doesn't stop at the kitchen bench.
- “Only on high” means it works, but louder. Fine for a smoke day, not every night.
- Too big for one unit? Two smaller units at opposite ends beat one working flat out.