Electric Furnace kW, Amps & BTU Calculator

Electric furnaces convert electricity to heat at 100%.

HVAC Pro calculator — inputs, formula and example are open to everyone.

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Formula

1φ: I = W ÷ V
3φ: I = W ÷ (1.732 × V)
BTU/h = kW × 3,412

Example calculation

15 kW at 240 V → 62.5 A, 51,182 BTU/h.

Practical HVAC use

Verify element staging.

Common mistakes

Forgetting reduced output at 208 V.

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Educational tool. Results are estimates from the stated formulas; always confirm with manufacturer data and the code adopted in your jurisdiction. All calculators