Plain-language guides to the numbers on an air purifier spec sheet, written by the same team that runs our tests. No medical claims, no ranking of products we have not measured.
How to use
The best spot for an air purifier in a bedroom, living room or office: how much space to leave, how close to the bed, whether to close the door, and the placement mistakes that waste clean air.
Running costs
Work out what an air purifier really costs per year in Thailand: electricity at your fan speed, replacement filters, and the three-year total. Includes simple formulas and worked examples.
Filters
What HEPA, True HEPA, H11, H12, H13 and H14 mean on an air purifier box, how much each grade actually captures, and why filter grade matters less than CADR and a good seal.
Buying guide
CADR (Clean Air Delivery Rate) tells you how much filtered air a purifier delivers per hour. Learn how it is measured, how to size a purifier to your room, and where the number falls short.