Laurie C. Fisher, a LEED Accredited Professional and director of sustainable design for Tucker Sadler Noble Castro Architects (www.tuckersadler.com), San Diego, offers the following about the impact of energy efficiency in designing and building for the future.Energy use is the largest contributing factor to greenhouse gas emissions, which ultimately contribute to global warming. Therefore, focus needs to be placed on using energy more efficiently and using less energy. Since buildings account for more than one-third of the total energy used in the United States, tremendous environmental benefits can be gained by improving energy efficiency in the built environment. Popular technologies being incorporated into new construction and existing facilities include photovoltaic panel systems, solar collectors, cogeneration systems, microturbines, net-metering, and third-party energy purchasing. In particular, photovoltaic systems are being incorporated into more residential and commercial projects. Photovoltaic systems are being installed directly onto rooftops and mounted on freestanding structures, which are used in some cases as carports to shade cars. In other cases, photovoltaic panels are laminated to insulation panels, or bonded to solar collectors that transfer the heat generated by the sun heating up the photovoltaic panels into the building. Currently, photovoltaic systems are being used or introduced as energy alternatives in a number of buildings in San Diego. Photovoltaic panels are being considered as a power source for the new San Diego Downtown Main Library, which currently is being designed for a site in East Village. To further maximize energy efficiency, integrated “green” design concepts also are being incorporated into existing buildings and new construction, including downsized, energy-efficient HVAC systems; high-performance windows; and added daylighting. These approaches have been shown to reduce energy and operating costs in buildings from 30 to 80 percent, compared to conventional buildings. Building energy codes are a means by which states can assure that buildings are relatively energy efficient. The energy codes that are currently available nationally – the International Energy Conservation Code (IECC) and the Model Energy Code (MEC) – are revised regularly as technology, construction practices, and market-driven forces improve the way buildings use energy. The value of energy efficiency in properly implemented construction standards is universally recognized as the easiest and most cost-effective way to help consumers save energy (and money) when installed at the time of construction.