Lets now pass to the overall performance. All air cleaner use the CADR index to measure performance.

CADR (Clean Air Delivery Rate) is the standard performance metric used to describe particle removal in portable room air cleaners. It is measured in cubic feet per minute (CFM) and can be understood as the equivalent amount of perfectly clean air the purifier delivers each minute. The key point is that CADR is not merely airflow: it reflects the combined effect of airflow and filtration efficiency.

In practice, high airflow through a moderately efficient filter can rival lower airflow through a very high-efficiency filter when the goal is to reduce particle levels in a room quickly.

CADR is useful because it translates cleanly into real-world outcomes:

• Cleaning speed: higher CADR reduces particle concentration faster.
• Room sizing: CADR converts into ACH (air changes per hour) for a given room volume: ACH ≈ (CADR × 60) / room volume.
• Realism check: maximum CADR is usually achieved at the loudest fan setting, so mid-range speeds often matter most for daily use. A practical strategy is “purge then maintain”: run a higher setting briefly to reset air quality, then step down to a quieter speed you can tolerate continuously.

Rule-of-thumb sizing (AHAM-style): a widely used heuristic is the “2/3 rule,” where Smoke CADR should be roughly ≥ 2/3 of the room’s floor area (sq ft). During heavy smoke events (e.g., wildfire periods), a stricter approach is Smoke CADR ≈ room area (sq ft) to clean more aggressively.

Airfanta provides the following measurements for its product from speed 1 up to speed 6:

Practical take: Speeds 2–4 are the daily-driver range (low-to-moderate power draw with manageable noise). Speeds 5–6 are best treated as short “purge” modes when maximum cleaning speed matters.

Another index is ACH, how many times per hour the purifier can theoretically process a room’s air volume (assuming good mixing). ACH ≈ (CADR × 60) / Room Volume. With 8 ft ceilings, room volume = floor area × 8.

Estimated ACH and minutes to reach ~90% particle reduction (t90) in typical rooms (8 ft ceilings, ideal mixing):

Note: t90 uses a well-mixed approximation: t90 ≈ ln(10)/ACH. Real rooms vary with leakage and airflow patterns.

Apart from the filter cost, there is also the electricity costs, that highly depend on your local tariff. Below are three electricity price scenarios (€/kWh) and two usage schedules: 24/7 and 8 hours/day. With local electricity in mind, we made some calculations of a possible electricity price scenario: with a low 0.18 €/kWh | Reference 0.2263 €/kWh | and High 0.30 €/kWh

Electricity cost at 8 hours/day (€/year)

Electricity cost at 24/7 (€/year)

The overall cost, even at full speed (6) for a whole year isn't bad, from 52 up to 87 euro. Some further examples of daily routines can translate from watts-per-speed into annual energy cost (not actual measurements-only caclulations).

Bottom line on costs: electricity is usually a minor contributor compared with filters in high-PM environments or wildfire periods; in clean-air environments, annual costs remain dominated by the replacement interval you choose.