Portable air filter purchasing guide
Who this is for
Anyone looking to choose suitable portable air filter for their home, classrooms, offices, or other indoor spaces to improve indoor air quality.
Main takeaways
Portable air filters, like HEPA filters, remove viruses and pollutants, improving indoor air quality.
Consider noise level, room size, replacement filter cost, and clean air delivery rate (CADR) when selecting a portable air filter.
The tool provided by Clean Air Stars can help you choose the right portable air filter for your needs.
Portable air filter purchasing guide
Portable air filters can improve indoor air quality by removing viruses, allergens, and other harmful particles from the air we breathe. They are a practical and relatively low-cost way to reduce airborne infection risks indoors, especially in shared spaces where ventilation may be limited.
Choosing the right air filter depends on several factors, including the size of your space, noise sensitivity, and available space.
Choosing the right filter for your space
When selecting a portable air filter, it helps to consider:
Room size or occupancy
Measure your room’s size (length × width in metres), and note how many people regularly use the room.
Larger rooms or rooms with more people usually need a more powerful filter or multiple smaller units.
Noise level
Think about how much noise you’re comfortable with. Quieter models (below 40-45 dBA) suit classrooms, offices, or meeting rooms.
Technology type and effectiveness
Avoid models that rely on technologies like ionisation, UV light, plasma, or photocatalytic oxidation.
Replacement filter cost
Consider the replacement filter cost, and check how often the manufacturer recommends they be replaced. It’s important to consider this so ongoing costs can be accounted for in budget planning to ensure continued use.
Does filtration reduce CO₂?
Portable air filters effectively remove airborne particles, viruses, and allergens. They don't, however, change CO₂ levels because they don't add fresh air into a space or remove gases. If your goal is to lower CO₂ levels, you will need to improve ventilation (by opening windows or adjusting mechanical ventilation if present).
How many portable air filters do you need?
It depends on the size of the room, and how many occupants are typically present. In smaller spaces with less occupants, one unit will work well. Larger spaces, crowded areas, or rooms with very poor ventilation might need multiple units spread out across the room.
What is CADR (Clean Air Delivery Rate)?
When choosing air filters, look for the Clean Air Delivery Rate (CADR).The higher the CADR rating, the more effective the filter is at cleaning air. It’s good to aim for 6 air changes per hour or more.
Need help choosing the right portable air filter?
We've linked to the helpful Air Cleaner Recommendation Tool provided by Clean Air Stars - a non-profit resource to help you choose appropriate models based on room size, occupancy, and preferred noise levels.