Air Purifier Not Working in Delhi Winter? What to Check
If indoor particle readings remain high, start by checking the equipment and the room. There is no universal outdoor AQI threshold above which every room purifier stops working, and a single study’s percentage reduction cannot predict every home.
Check these five things first
- The space being treated. Include connected areas and ceiling height when checking the manufacturer’s room rating. A unit in a hallway may not treat a closed bedroom as intended.
- The operating setting. Note the actual fan speed, including automatic or sleep-mode changes. Compare results at a setting you can use consistently.
- Filter condition and fit. Follow the manufacturer’s replacement schedule and confirm that filters are installed correctly.
- Airflow around the unit. Keep the inlet and outlet clear of curtains, furniture and other obstructions.
- Sources and openings. Log cooking, incense, smoking, open doors and windows alongside the readings.
EPA’s guide to home air cleaners explains room sizing, clean air delivery rate (CADR), operating speed and placement. Those factors are more useful for choosing equipment than purchase price alone.
Compare readings on the same basis
Keep the monitor in a consistent, representative position away from the direct clean-air outlet. Record indoor PM2.5, outdoor conditions, room use and the equipment setting over comparable periods. A brief cooking spike and an overnight average answer different questions.
Check whether the display is reporting PM2.5 concentration or an AQI scale. Do not compare a momentary value directly with a guideline defined over a day or a year. Our PM2.5 measurement guide explains that distinction.
Why one percentage reduction is not a guarantee
Indoor particles reflect outdoor entry, indoor emissions, removal and movement between rooms. Those change with the building and how it is used. A purifier test in one office cannot establish a fixed reduction limit for all Delhi homes.
Similarly, a fresh-air system does not make outdoor entry or indoor sources disappear. Its result needs to be checked in the actual installation. Claims of zero infiltration or a guaranteed recovery time after every window opening are not a sound basis for choosing equipment.
Assess ventilation separately
A particle filter does not supply outdoor air. If the question is whether an occupied bedroom gets enough outdoor-air exchange, investigate ventilation separately using a suitable CO₂ measurement and room-use log. See the bedroom CO₂ guide.
When to consider a whole-home system
If your requirement includes filtered outdoor-air supply across several rooms, ask for an installation assessment. For aqi0, that covers the intake, supply path, room connections, power, service access and normal exhaust use.
aqi0 is a standalone whole-home air purifier using H13 HEPA-filtered outdoor air and positive pressure. Read the system specifications and performance conditions. Compare the options in our fresh-air system versus purifier guide.