1. What pollutant are you trying to reduce?
Particles, odors, gases, moisture and carbon dioxide are different problems. Define the problem first, then choose the technology.
2. What is the room volume?
Measure floor area and ceiling height. Volume gives a more useful picture of how much air the system must treat.
3. What airflow data is available?
Look for transparent airflow or clean-air delivery information and identify the operating mode at which it is measured.
4. What filters are included?
Check the particle-filter class, carbon stage and any pre-filters. Ask what each stage is designed to do.
5. Is the housing well sealed?
A high-quality filter is less useful if air can bypass it through gaps around the frame.
6. What noise level will you actually use?
Compare realistic daily operating modes, not only maximum fan output.
7. How are filters replaced?
Service access affects whether maintenance happens on time. Ask about tools, replacement cost and availability.
8. Does placement fit the room?
Consider furniture, walls, doors, HVAC diffusers and installation clearances.
9. Is ventilation also needed?
If occupancy-related CO₂ or fresh-air supply is a concern, recirculating filtration alone is not enough.
10. Are sensors useful and understandable?
Sensors can help, but understand what they measure, where they are located and whether readings represent the whole room.
11. What is the installation requirement?
Portable, wall and ceiling systems involve very different electrical, structural and service considerations.
12. Is the product documentation clear?
A good technical decision is easier when the manufacturer explains specifications, limits, maintenance and intended use without relying only on marketing language.
Related reading
Continue with our complete Indoor Air Knowledge Hub or read about PM2.5, VOCs and CO₂.