Furnace & Heating Efficiency Calculator

Efficiency is output divided by input.

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

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Formula

η = output ÷ input × 100

Example calculation

76,000 out ÷ 80,000 in → 95%.

Practical HVAC use

Checking rating-plate data.

Common mistakes

Treating a calculation as a combustion analysis.

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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