Reducing heat loss through window retrofitting

Provides table showing that annual heat loss through windows in U.S. accounts for about 5% of total energy consumption, or around 1.5 times energy derived from oil transported by alaskan pipeline, costing $30 billion annually. Describes relatively simple window treatment to eliminate substantial portion of thisloss which involves tightly sealed, interior-applied insulating panels. Demonstrates how performance of several such systems was predicted and verified by standard test methods. Finds panels reduce heat loss through steel-sash windows by factor of 4 when infiltration is not present, and by factor of 8 when it is.