Key Takeaways
- Fan or aircon during haze? You have 3 aircon modes plus your fans, and none of them cleans the air. The choice is about comfort with the windows shut. If a service is due once the haze clears, FoamJet servicing for 2 units costs $46 and takes about 60 minutes, as shown when booking.
- Keep the flat shut first, then pick a mode. Windows and doors closed is what limits how much haze comes in. Fans and aircon only move or cool the air already inside.
- Cool mode for hot rooms, dry mode for muggy days, fan mode for cooler evenings. All 3 recirculate room air. A split aircon doesn’t draw in outdoor air.
- A ceiling fan with the windows shut is fine. Point standing fans away from any open window, or they can pull haze in.
- For health advice and live PSI readings, go to NEA’s official haze site, haze.gov.sg.
A Shut Flat in Jurong West
It’s a Sunday afternoon in a 4-room HDB flat in Jurong West, and the haze has been hanging around for days. The windows are shut, the living room is getting warm, and the aircon has been on since breakfast. Is the standing fan enough for the afternoon, or should the aircon stay on?
Should You Use a Fan or Aircon During Haze?
Use whichever keeps you comfortable with the windows shut, because neither a fan nor an aircon cleans the air. A fan moves the room’s air around. A wall-mounted split aircon pulls in the room’s air, passes it over a cold coil and through a mesh dust screen, and blows it back out. It doesn’t bring in air from outside.
So the real decision during haze isn’t “fan or aircon”. It’s “how do I stay cool enough to keep the windows closed?” In Singapore’s heat, that usually means the aircon for at least part of the day, with fans helping it along.
What Do Fan, Dry and Cool Modes Actually Do?
Each mode runs the same indoor blower. What changes is whether the unit cools the air, and how hard.
| Option | What it does | Cools the air? | Brings in outdoor air? | Good during haze for |
|---|---|---|---|---|
| Standing or wall fan | Moves room air | No | Only if pointed at an open window | Short spells, cooler hours, windows shut |
| Ceiling fan | Moves room air across the whole room | No | No | Keeping a shut room from feeling stuffy |
| Aircon fan mode | Runs the blower without cooling | No | No | Evenings that are warm but bearable |
| Aircon dry mode | Cools gently to take moisture out of the air | A little | No | Muggy, humid days that aren’t too hot |
| Aircon cool mode | Cools to the temperature you set | Yes | No | Hot afternoons and nights with the flat shut |
None of these options filters out haze. The aircon filter is a mesh dust screen, not a HEPA filter, so it catches dust and lint, not fine smoke particles. If you want a device built to lower particle levels in a closed room, our guide to air purifier vs aircon during haze explains the difference.
Can You Use a Ceiling Fan With the Windows Shut?
Yes, and it’s one of the most useful things to do in a shut flat. A ceiling fan keeps the air moving, which makes a closed room feel less stuffy, and it can let you set the aircon a little warmer for the same comfort.
A few things to watch:
- Keep windows and doors shut while it runs. A fan near an open window draws outdoor air in.
- Don’t point standing fans at the window to “air out” the room during haze.
- Wipe the blades if they’re dusty, so the fan isn’t spreading dust around the room.
- If the fan wobbles, hums or won’t start, switch it off. Our guide to a ceiling fan not working covers safe checks.
Which Aircon Mode Is Best During Haze?
Pick the mode by how the room feels, not by the PSI. All 3 modes recirculate room air, so none is “safer” than another for haze.
- Hot room, afternoon sun: cool mode. It’s the one that actually brings the temperature down, so you’re not tempted to open a window.
- Warm and sticky, but not hot: dry mode. It cools gently and takes moisture out of the air, which helps on humid days when cool mode feels too cold.
- Cooler evening: fan mode, or just the ceiling fan, with the windows still shut.
Whatever the mode, keep the mesh filters clean. Haze days often mean the aircon runs for longer than usual, and dust builds up faster. Our guide to using your aircon during haze covers filter care step by step.
What Can You Do Yourself, and What Needs a Technician?
Most of the haze-season routine is a DIY job:
- Rinse the mesh filters under a tap, dry them in the shade and refit them. Never run the unit without filters.
- Wipe the front panel, vanes and fan blades with a damp microfibre cloth.
- Keep the flat shut and use fans to spread the cool air around.
Leave the inside of the unit to a technician. The coil, blower wheel and drain tray sit behind the casing, and cleaning them needs the unit opened up. Call for help if:
- airflow stays weak after the filters are clean;
- the unit smells musty, or smells like smoke or burning from the unit itself;
- water drips from the indoor unit.
A burning smell is a switch-off-now problem, not a haze problem.
When Should You Book an Aircon Service?
Book one once the haze has eased, if the unit worked hard through it and the last service was a while ago. Urban Company’s aircon servicing uses FoamJet. A technician applies foam to the evaporator coil and blower wheel, rinses it off with the loosened dirt into a catch bag, and tests the unit afterwards. It cleans the unit, not the air in your flat.
Check what’s included and book aircon servicing in Singapore. For health advice during haze, follow NEA’s advisories on haze.gov.sg. For more guides, browse our aircon servicing guides.
Frequently Asked Questions
Is it OK to use a fan during haze?
Yes, as long as the windows stay shut. A fan only moves the air already in the room. It doesn’t cool it, filter it or bring in air from outside. Pointed at an open window, though, it can pull haze in, so close up first. For health advice and live readings, check haze.gov.sg.
Which aircon mode should I use during haze?
Cool mode if the room is hot, dry mode on muggy days when it’s warm but not stuffy, and fan mode on cooler evenings. All 3 recirculate the room’s air. None of them brings in outdoor air or cleans the air, so the choice is about comfort, with windows and doors kept shut.
Can I run the ceiling fan with the windows shut?
Yes. A ceiling fan is a good partner to a shut flat. It keeps the air moving so a closed room feels less stuffy, and it can let you set the aircon a little warmer. It doesn’t filter anything, so it won’t change how much haze is in the room.
Does aircon fan mode bring in air from outside?
No. On a standard wall-mounted split aircon, fan mode runs the indoor blower without cooling. It recirculates the room’s air through the mesh filter and back out. The outdoor unit only releases heat when cooling, and neither unit draws outdoor air into the flat.
Is it safe to sleep with the aircon on during haze?
Running a well-maintained aircon overnight is normal in Singapore, and it lets you keep the windows shut. Make sure the filters are clean and the unit isn’t dripping or smelling of burning. For any health question about haze, follow NEA’s advisories on haze.gov.sg rather than general advice.
Does my aircon need servicing after the haze?
Not automatically. Rinse the mesh filters first. Book a service if airflow stays weak, the unit smells musty, water drips from the indoor unit, or the last service was months ago. A technician cleans the coil, blower wheel and drain tray, which a filter rinse can’t reach.