New technologies in polyurethane foam offer window installers a choice.
In order to maintain the warranties, contractors had to use other means to offer insulating and energy efficient properties. One option was to chink fiberglass into crevices around windows; however, once the strands of glass are compressed and broken during this packing process, the fiberglass no longer provides an appreciable amount of insulation. Chinked fiberglass also allows for moisture to flow into the cavities, which can lead to even larger problems such as mold, mildew and rot.