Surface Condensation Risk Calculator

Surfaces at or below dew point condense.

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

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Formula

Margin = surface temperature − dew point

Example calculation

72 °F, 45% RH air (dew point 49.6 °F) over a 48 °F duct → condensation.

Practical HVAC use

Duct insulation, cold water lines, windows.

Common mistakes

Measuring air conditions far from the surface.

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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