Buying by spec
What numbers and certifications to look for. No brands, no affiliate links.
Air purifier specs that matterCADR, true HEPA, noise at sleep speed, filter supply and running cost. A checklist for comparing any purifier without trusting the marketing.Filter grades decodedHEPA H13 vs H14 vs "HEPA-type", MERV ratings for DIY and ducted systems, and when carbon filters matter.Indoor air monitor specsWhat to look for in a PM2.5 monitor, which extra sensors are worth having, and which aren't.Respirator specs and how to spot fakesWhat N95, FFP2, BIS IS 9473 and KN95 mean, and how to check a respirator is genuine.Sealing materialsWhich weatherstrips, door sweeps and sealants suit which gap, including renter-friendly options.Fresh-air and ventilation systemsWhen a filtered fresh-air system is worth it, what specs to ask for, and how it fits with room purifiers.Car cabin filters and in-car airA better cabin filter and the recirculation button do most of the work. In-car purifiers rarely add much.Red flags when shoppingMarketing claims to ignore, and the signs of a fake mask or an underpowered purifier.