Thermal Performance Measurements of Sealed Insulating Glass Units with Low-E Coatings Using the MoWitt Field Test Facility

Using data obtained in a mobile field-test facility, measured performance of clearsand low-emissivity double-glazing units is presented for south-facing and north-facingsorientations. The changes in U-value and shading coefficient resultingsfrom addition of the low-E coating are found to agree with theoretical expectationssfor the cold spring test conditions. Accurate nighttime U-values weresderived from the data and found to agree with calculations. Expected correlationsbetween U-value and wind speed was not observed in the data; a plausible experimentalsreason for this is advanced.