In 1997, market share for energy-efficient windows stood at 13 percent. With very little information known about energy-efficient windows, demand for the product was low. And with manufacturers resistant to incur the up-front costs required to produce energy-efficient windows, availability was minimal. A year later, ENERGY STAR® released its first efficient window standard (u-.35) leaving manufacturers wondering how to cost-effectively change their processes to comply with the new specification. Seeing an opportunity to increase market share for efficient windows, we worked with manufacturers to find simple ways to qualify their products and affordable manufacturing processes to help reduce the cost barriers.