Surface Condensation Risk Calculator
Will a cold surface sweat? Compares surface temperature against indoor dew point.
This is the entire science of pipe lagging: keep the jacket surface above the room dew point. At 26 °C/60% RH the dew point is 17.6 °C — bare chilled lines always sweat.
Formula
Surface Condensation Risk Calculator is a free condensation risk for HVAC designers, technicians and energy auditors — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Surface Condensation Risk Calculator
Will a cold surface sweat? Compares surface temperature against indoor dew point. The calculation implements T_dew (Magnus); condensation when T_surface ≤ T_dew (ASHRAE Handbook — Fundamentals; Magnus-Tetens relation). This is the entire science of pipe lagging: keep the jacket surface above the room dew point. At 26 °C/60% RH the dew point is 17.6 °C — bare chilled lines always sweat.
How to use Surface Condensation Risk Calculator
- 1Enter Room air temperature in °C.
- 2Enter Room RH in %.
- 3Enter Surface temperature in °C (Chilled pipe, duct, window, slab…).
- 4Read Air dew point, Surface margin above dew point instantly — no submit button needed.
Why use Surface Condensation Risk Calculator?
- ✓Implements the standard formula — T_dew (Magnus); condensation when T_surface ≤ T_dew
- ✓Reference cited on-page: ASHRAE Handbook — Fundamentals; Magnus-Tetens relation
- ✓Built-in engineering verdict flags out-of-range results instantly
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Surface Condensation Risk Calculator use?+
It computes T_dew (Magnus); condensation when T_surface ≤ T_dew, per ASHRAE Handbook — Fundamentals; Magnus-Tetens relation. The formula is displayed under the result.
What should I keep in mind when using this calculator?+
This is the entire science of pipe lagging: keep the jacket surface above the room dew point. At 26 °C/60% RH the dew point is 17.6 °C — bare chilled lines always sweat.
Is this based on ASHRAE methods?+
The calculations follow the standard ASHRAE/ISHRAE formulations cited under the result, simplified where industry practice does the same. For permit-grade design, confirm with the full code procedure.
Is the Surface Condensation Risk Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
Related Engineering tools
Reynolds Number Calculator
Compute Re from density, velocity, pipe diameter and viscosity — with instant laminar/turbulent classification.
● LiveLaminar vs Turbulent Flow Classifier
Classify hydraulic-oil or process-fluid flow regime from kinematic viscosity, line velocity and tube bore.
● LiveBernoulli Equation Solver
Solve downstream pressure between two points from velocities, elevations and fluid density (ideal, lossless).
● Live