JANUARY JLC 1999 CHOOSING Energy- Efficient Windows New high-performance glazings can cut heating and cooling costs, but you have to choose the right windows for your climate. There are more than 90 million homes and approximately 19 billion square feet of windows in the U.S. alone. It is estimated that over half of these still have singlepane glazing. Most of these homes are more than 20 years old and, as a result, the market for insulated glass units (IGUs) in replacement windows is growing at breakneck speed. At the same time, "high performance" options have multiplied over the last few years. Choosing the right product can cut heating costs up to 25% and cooling costs by as much as 40%. Some
