Spectrally Selective Low-E Detector Reassures Builders

Photo of the simple hand-held detector created by Berkeley Lab scientists
December 1998

With DOE and CIEE co-support, researchers Dariush Arasteh, Brent Griffith, Chad Goudey, Christian Kohler, and Daniel Turner developed a prototype of a simple hand-held detector to determine the coating (none, regular low-e, or spectrally selective low-e) on a double-glazed window. An infrared light-emitting diode and phototransistor measure reflectance in the near-infrared portion of the solar spectrum (where coating technologies have significantly different reflectances, which can't be detected by the human eye). One of three LEDs then illuminates, indicating which of the coatings is present.

The detector was recently tested by consultants at ConSol Inc. of Stockton, California, who were involved in several tract developments where spectrally selective low-e windows were specified to meet the California energy code or ENERGY STAR® homes criteria.