Measurement of Fenestration Performance Under Realistic Conditions

The need for fenestration performance measurements under realistic conditions is noted, and the Mobile Window Thermal Test facility (MoWiTT), newly constructed at LBL to make these measurements, is described. A key feature of the MoWiTT is the direct measurement of instantaneous net energy flow in the presence of sunlight. Ongoing calibration to establish the accuracy of this facility is described, and calibration data so far obtained are presented. Estimates from these data indicate that the facility will have sufficient accuracy for most fenestration measurements of interest.