【NEW】Dreame Air Purifier Fan NP10 l Washable Filter

Clean air delivery rate: how many cubic metres of filtered air the purifier delivers per hour at top speed. It's the most useful number for comparing purifiers.

HDB rooms are about 2.6 m high, so a room needs roughly room m² × 10 of CADR to clean all its air every 15 minutes. That's fast enough to clear haze or cooking smoke. For example, a 12 m² bedroom needs about 120 m³/h, and a 30 m² living and dining area needs about 300 m³/h.

The room size the manufacturer rates the purifier for. Brands calculate this in different ways.

Typical HDB sizes: common bedroom 9–12 m², master bedroom 12–15 m², 4/5-room living and dining 25–35 m². For a like-for-like comparison, use the CADR room guide in the table.

How well the filter traps tiny particles such as dust, pollen and pet dander. HEPA grades come from the European EN 1822 test: H12 captures at least 99.5%, H13 at least 99.95%, H14 at least 99.995%.

0.3 µm is about 1/200 the width of a human hair, and around the size that is hardest for filters to catch. PM2.5, the particle size reported during haze, is under 2.5 µm.

Loudness in decibels (dB). Every 10 dB higher sounds about twice as loud.

30 dB is a whisper or quiet bedroom. 40 dB is a library. 50 dB is a quiet office. 60 dB is normal conversation. 70 dB is busy traffic. For a purifier that runs overnight, the lowest figure is the one you'll hear while you sleep.

How long one filter lasts with typical use before it should be replaced.

Humidity and haze season can shorten it. Go by the filter indicator in the app or on the unit, and replace the filter sooner if airflow drops or it starts to smell.