Archive · 11 Dec 2025
Key Specifications to Consider When Buying an Air Purifier
When buying an air purifier, it's important to look at three main things: HAC, which includes HEPA and activated carbon filters, and CADR.
The HEPA filter catches tiny particles like dust and smoke, while the activated carbon filter absorbs gases and bad smells.
CADR tells you how fast the purifier can clean the air.
For a 150 sq ft room, you should look for a purifier with a CADR of around 300.
Also, check the filter life, noise levels, placement, power consumption, and if it has a real-time AQI display to see if it's working well.
HAC (HEPA and activated carbon filters) and CADR are key specifications for air purifiers.
HEPA 13 is ideal for homes, capturing fine particles that can cause health issues.
Activated carbon filters absorb harmful gases, smoke, and odours.
CADR indicates how quickly the purifier can clean the air; match it to your room size.
Consider filter life, noise levels, placement, power consumption, and real-time AQI display when choosing a purifier.
- Who
- Dr Sulaiman Ladhani, consultant pulmonologist, and Dr Harish Chafle, senior consultant chest physician
- What
- Key specifications to consider when buying an air purifier
- When
- Not specified
- Where
- Indian cities, homes, hospitals
- Why
- To improve indoor air quality and protect against pollution
- HAC
- Includes HEPA filter and activated carbon filter
- CADR
- Clean Air Delivery Rate
- HEPA 13
- Ideal for homes, captures fine particles
- HEPA 14
- Stronger, usually reserved for hospitals
- Activated Carbon Filter
- Absorbs harmful gases, smoke, and odours
- CADR Calculation
- Room size (in sq ft) × 2 = Recommended CADR
- Filter Life
- HEPA and carbon filters require regular replacement
- Noise Levels
- Check decibel ratings, especially for night mode
- Placement
- Keep the device a few inches away from walls
- Power Consumption
- Energy-efficient models are beneficial
- Real-time AQI Display
- Helps monitor air quality improvement