A worked bedroom example
A 4 m × 3 m room with a 2.4 m ceiling contains 28.8 m³. An illustrative target of four air changes per hour requires 115.2 m³/h. Four is an editable planning assumption, not a health guarantee or a recommendation for every room. Open doors, poor air mixing and ongoing particle sources change the real result.
Read the fan speed behind the claim
The EPA advises choosing a particle cleaner with enough CADR for the room, and notes that higher fan speeds and longer operation filter more air. Maximum CADR is not automatically the output in sleep mode. Look for noise and throughput reported at the same speed, especially for a bedroom.
Source: US EPA: Guide to Air Cleaners in the Home ↗Keep units and pollutants consistent
Use m³/h throughout. A figure in cubic feet per minute needs multiplying by approximately 1.699. Smoke, dust and pollen CADRs may differ; do not silently average them. Particle filtration also says little about gas or odour removal. This is a sizing estimate, not a prediction of individual health outcomes.
Source: US EPA: Guide to Air Cleaners in the Home ↗Your pre-purchase checklist
- Measure ceiling height as well as floor area.
- Check pollutant basis, units and fan speed.
- Budget for replacement filters and check their availability.
Sources and scope
Original editorial guidance with linked source material. Manufacturer guidance describes operation and features; it is not independent testing. Calculator results use your inputs and stated assumptions.
- US EPA: Guide to Air Cleaners in the Home ↗Public agency guidance