From a 25 W desk fan to a 2 kW industrial blower: enter the power draw, hours and your tariff to get the running cost, and optionally compare a second fan to see whether a more efficient model pays for itself. Uses real input watts, not the "motor rating" printed on the box.
Cost = kW × hours × price. Speed setting applies the cube law to the power draw.
Engineering estimate for preliminary sizing. Verify against the fan curve, local codes and your system measurements before purchase. Ask a Longwell engineer to check your duty point free of charge.
Use input watts. The "motor power" on a fan's box is often the rated output of the motor or a marketing figure; a plug-in energy meter gives the real number. For industrial fans, measure current with a true-RMS clamp meter and use the motor tool to convert to watts.
| Fan | Typical input (AC motor) | Efficient (EC / BLDC) | Annual cost, 8 h × 150 d @ 0.15 |
|---|---|---|---|
| Desk fan 20–30 cm | 25–40 W | 3–12 W | 4.5–7 vs 0.5–2 |
| Pedestal / stand fan 40 cm | 45–70 W | 15–30 W | 8–13 vs 3–5 |
| Box fan 50 cm | 90–120 W | — | 16–22 |
| Air circulator | 60–100 W | 25–45 W | 11–18 vs 4.5–8 |
| Ceiling fan 130 cm | 60–100 W | 25–35 W | 11–18 vs 4.5–6 |
| Tower fan | 40–60 W | 20–30 W | 7–11 vs 3.5–5.5 |
| Bathroom exhaust fan 100 mm | 15–25 W | 4–8 W | 2.7–4.5 vs 0.7–1.4 (8 h/d) |
| Inline duct fan 150 mm | 60–100 W | 30–50 W | 11–18 vs 5.5–9 |
| Industrial drum fan 60 cm | 350–600 W | — | 63–108 |
| Condenser / axial 450 mm | 250–500 W | 150–300 W | 45–90 vs 27–54 |
A fan's airflow per watt (m³/h/W or CFM/W) is the honest efficiency figure: 25–40 CFM/W for a good DC air circulator, 10–20 for an AC box fan, 100+ for an HVLS ceiling fan at low speed.
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<a href="https://www.longwellfans.com/resources/fan-electricity-cost-calculator/">Fan Power Consumption & Electricity Cost Calculator</a> by LONGWELL FansAPA: LONGWELL Fans. (2026). Fan Power Consumption & Electricity Cost Calculator. https://www.longwellfans.com/resources/fan-electricity-cost-calculator/
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