Ouside temperature, inside air condition and condensation on inside glass windows
The combination of outside temperature and inside air condition - relative humidity, and the moisture condensation on inside glass windows are indicated in the charts bellow.
Windows - Overall Heat Transfer Coefficients U
- Single glass window : U = 1.13 (Btu/ft2 oF hr) = 6 (W/m2 oC)
- Double sealed glass window : U = 0.58 (Btu/ft2 oF hr) = 3 (W/m2 oC)
Example - Condensation on Window Surface
With an indoor relative humity of 50% and a single - aprox. 6 (W/m2 oC), 1.13 (Btu/ft2 oF hr) - condensation will occur at 6oC (43oF) and below.