Getting your home ready for haze, room by room

Updated 15 October 2026 · By the purifierplan.com team

Shutting windows keeps out less haze than most people expect. Filtering the air in the rooms you actually use makes the larger difference.

What the measurements say

Only a few Singapore homes have been measured during haze, so treat these figures as indications, not averages.

Figures from single apartments, tabulated in the NCCEH indoor/outdoor evidence review (2026). Results vary with the building, the room and the purifier.

Room by room

Living room

If your living room is open to the dining area, kitchen or corridor, it's one large body of air. A single small purifier won't clean all of it to the same level. Either size for the whole open area (see how to size a purifier) or put the purifier where people sit, away from the kitchen.

Bedrooms

You spend 7 or more hours here at a stretch, so a bedroom is often where a purifier makes the biggest difference to what you breathe at home. Keep the door shut so the purifier only has to clean the room's own air. Choose a model that reaches the room's target at a speed quiet enough for you to sleep with.

Kitchen

Cooking adds particles of its own. Use the cooker hood while cooking. If the kitchen is open to the living room, a living-room purifier will also be working on cooking smoke.

Air-conditioned rooms

Split air-conditioners recirculate the room's air and don't bring in outdoor air, so running one doesn't add haze. It doesn't seem to remove much either: the one Singapore measurement with air-con on found indoor levels at about 72% of outdoor. A purifier in the same room does the filtering.

Windows and doors to the outside

Keep them shut while the haze lasts, and open them for fresh air when NEA's readings drop. A purifier cleans particles, not stale air: in a small room with the door and windows shut all night, carbon dioxide from breathing builds up.

Placement and set-up

• Space around it: leave clearance around the air intake and outlet as the manual says. Pushed into a corner or behind furniture, a purifier delivers less clean air to the room.
• Where people are: closer to where you sit or sleep is better than a far corner of a big room.
• Filter: check it's fitted and its plastic wrapping is removed. Replace it at the interval the manufacturer gives; see the running costs in our 4-room example.
• Run it continuously during haze. Indoor levels take time to come down after you switch on, so a purifier run only when the air seems bad does much less.

Know today's readings

Check the 24-hour PSI for the official band and the 1-hour PM2.5 for right now. How to read NEA's readings explains both.

Health advice comes from MOH

MOH and NEA give advice by PSI band for three groups: healthy people; older people, pregnant women and children; and people with heart or lung conditions. MOH describes portable air purifiers as a way to further reduce indoor particles. It advises N95 masks for prolonged time outdoors when the PSI is forecast above 300, or above 200 for people with chronic heart or lung disease, and says they aren't needed indoors. If you feel unwell, seek medical attention. See HealthHub (reviewed 11 October 2026) for the full advice.

A purifier is not a medical treatment. This page gives practical information about indoor air, not medical advice.

Sources

• NCCEH, Indoor/outdoor evidence review, appendices (February 2026), tabulating Singapore studies from 2015 and 2019.
• Wong et al. 2002, bedroom monitoring in Singapore: split air-conditioners have no fresh-air intake; overnight CO₂ was higher in air-conditioned bedrooms.
• HealthHub (MOH), How to protect yourself against haze, reviewed 11 October 2026.
• This page is not affiliated with or endorsed by NEA, MOH or HDB.