Airfire AP309 user manual
✓ Confirmed fit — Airfire AP309 & AP409 air purifiers
- Filter type: True HEPA H14 (medical-grade)
- Design: two-stage system — a washable pre-filter plus a separate H14 HEPA element
- Replace: every 3–5 months (about 2,500 hours)
Not sure this is your model? The AP309 and AP409 open from a removable front panel that snaps off at the side gap. Inside you'll find a washable pre-filter sitting in front of a separate H14 HEPA element. If your unit matches this — panel snaps off, two-part filter — this is the right replacement.
When to replace your filter
- Replace every 3–5 months, or roughly every 2,500 hours of use.
- Your purifier's HEPA indicator light turns on (and keeps flashing) when it's time.
- Replace sooner if you notice weaker airflow, less odor removal, or you run it in heavy smoke or pollution.
- After fitting a new filter, hold the HEPA button for 5 seconds to reset the indicator.
How to replace the filter
Safety first: unplug the power adapter before you start.
- Gently snap the front panel at the side gap to unlock it, then lift it off.
- Take the old filter out.
- Remove the plastic wrap from the new H14 filter. Running the purifier with the wrap still on blocks airflow and can cause it to overheat.
- Place the new filter in, then put the washable pre-filter back in front of it.
- Refit the front panel until it clicks into place. Plug back in, then hold the HEPA button for 5 seconds to reset the indicator.
Keep your filter working between changes
- Vacuum the washable pre-filter about once a month.
- Brush or vacuum the white side of the HEPA filter monthly to clear hair and dust.
- Never wash the H14 HEPA element with water — it damages the filter material. (Only the pre-filter is washable.)
- Keep humidity below 85% RH; moisture can cause the filter to grow mold.
AP309 / AP409 quick specs
| Filter | True HEPA H14 + washable pre-filter |
| Replacement | Every 3–5 months (~2,500 h) |
| Power | 100–240V, 50/60Hz, 36W |
| Noise | 22–58 dB |
| Speeds & modes | 4 speeds (Low / Medium / High / Pet), Auto, Quiet Sleep, Timer 2–8 h |
| Air quality light | Blue 0–35 · Green 36–75 · Yellow 76–115 · Red 116+ (PM2.5) |
Troubleshooting
- Replace light still on after changing the filter? Hold the HEPA button for 5 seconds to reset it.
- Reduced airflow or odor removal? Vacuum the pre-filter, make sure the back grille isn't blocked, or replace the filter if it's due.
- Excessive noise? Place the unit on a flat, level surface.
- Not feeling the effect? Check the filter is seated correctly, the intakes aren't blocked (keep 20 cm clear), and the room size suits the unit.