High-performance windows protect the air-conditioned space inside your home or building from the hot, dry climate and provide several important benefits.

In addition to lowering equipment and utility costs by allowing you to opt for a smaller HVAC system, high-performance windows help utility companies reduce peak cooling loads. These two benefits working in tandem reduce energy consumption while maintaining a comfortable indoor environment and minimizing greenhouse gas emissions.

In hot climates, the peak cooling load refers to how much air conditioning capacity is needed to maintain a comfortable indoor temperature, typically 75 degrees Fahrenheit on especially hot days. Meeting peak demand, however, isn’t necessary most of the time. In fact, it varies with the time of day and the time of year, and it seldom occurs for more than several hours per month.

Nevertheless, peak demand presents a dilemma for utility companies. They must maintain adequate capacity to meet customer demand – even during the hottest summer days when many people run their air conditioners constantly.

Remaining poised to meet peak cooling demand can create additional expenses for consumers. Some utility companies implement demand charges to cover the high costs they pay for their generating and transmitting capacity even though it sits idle most of the time.

By minimizing peak cooling loads, utility companies bypass the need for additional generating capacity. This allows them to circumvent the expense of building new power plants. It also benefits their customers by keeping rates down.

Windows are typically the largest source of unwanted heat gain in homes and buildings. According to the U.S. Environmental Protection Agency (EPA), even the best-performing windows provide less insulation than the worst walls or roofs. Windows are also a common source of air leakage.

Furthermore, windows that allow high solar gain create additional heat into your home or building, where it’s already being generated by people, lights, equipment, and appliances. Eliminating windows is normally impractical and undesirable, yet replacing them is often economically feasible, particularly when part of an extensive renovation.

In fact, the windows and glazing systems in homes and buildings constructed during the 1970s and earlier are beginning to fail. These systems are often comprised of single-pane glass. A home or building with windows that need replacing offers an opportunity to make upgrades that contribute to reducing peak cooling loads.