PureAirIndex · Guide
How much does it cost to run an air purifier 24/7?
Yearly electricity cost = watts × hours per day × 365 ÷ 1,000 × your rate per kWh. Below, that formula applied to the derived operating watts of 247 ENERGY STAR certified models.
Running-cost calculator
263 kWh/yr → $42.05 per year · $3.50 per month
24/7 cost by purifier size
Median derived operating watts per smoke-CADR range, run continuously on its tested setting. Rates are hypothetical flat prices.
| Smoke CADR | Models | Median watts | kWh/yr at 24/7 | At $0.10 | At $0.16 | At $0.25 |
|---|---|---|---|---|---|---|
| 0–<100 cfm | 49 | 9.2 | 81 | $8.06 | $12.89 | $20.15 |
| 100–<200 cfm | 83 | 21.5 | 188 | $18.83 | $30.13 | $47.09 |
| 200–<300 cfm | 44 | 37.5 | 329 | $32.85 | $52.56 | $82.13 |
| 300+ cfm | 71 | 56.0 | 491 | $49.06 | $78.49 | $123 |
ENERGY STAR's own annual figure (median 152 kWh/yr) assumes a mix of standby and active use, not 24/7 on one speed. Running continuously uses about 1.48× that reported figure for the median model (range 1.01×–1.55×).
What this cost does not include
- Lower speeds: most units draw far less on quiet settings; derived watts reflect the tested setting.
- Filters: replacement filters often cost more per year than electricity. Use the 2-year cost calculator with prices you verify.
- Time-of-use or tiered electricity pricing.
Derived watts = smoke CADR ÷ certified CADR per watt, across 247 records. Full analysis: energy-use study · methodology.