Condensation tests on glass samples for energy efficient windows

This article presents results from a pilot study comparing condensation patterns on small glass samples with different surface properties. Experiments were carried out on three commercial glass samples (clear float, TiO2-coated and SnO2-coated) to see how water condensed on the different surfaces. The experiments were carried out under a clear night sky in Uppsala, Sweden. It was found that the pane with the low-emittance coating stayed clean of condensation longer than the other two. In the morning, the water layer on the TiO2-coated sample was smeared out so that it was possible to see through that pane, while the view through the other two was still blurred. The TiO2 coating does not prevent condensation, but makes it easier to see through the water layer. These simple tests indicate noticeable differences between different surface materials and also that these effects can be studied by exposing small samples to a clear night sky without having to perform full scale tests.