Residential mechanical ventilation systems will not reach their performance potential if components are poorly manufactured or installed improperly. Several factors contribute to poor performance including long duct lengths and compression in flexible ducts, resulting in a loss of ventilation rate and a significant increase in power and energy consumption by HVAC systems.
The distribution system is an integral part of many mechanical ventilation systems. It can have a significant effect on the ventilation rate and efficiency of a building. Duct leakage is a source of energy loss, ventilation rate loss, and a source of indoor pollution (in return ducts).
High performance lighting with optional controls is a key element for a more comfortable and energy efficient home. There are several technologies beginning to be available today that could have the same transformative effect on energy efficiency in homes. LED, or light emitting diode, lighting systems are currently being developed that could reduce the energy use dramatically.
HVAC systems need to be properly sized so the home will be comfortable amid the harshest outdoor conditions. If a unit is oversized, energy costs may increase and the home may experience high temperature swings during milder weather.
Consumers face many considerations when selecting a new water heater for their home. There are several types of high efficiency water heaters, each with different advantages and payback periods.
Dramatic improvements in fenestration technologies in recent years have revolutionized performance. A good example of this change is the adoption of Low-E window technology in the 1990s, a period when almost all windows installed in homes were clear glass. By 1995, the first national standard for measuring solar heat gain co-efficient (SHGC) for windows was developed. When minimum SHGC ratings were first incorporated into energy codes in the year 2000, most manufacturers were no longer making clear glass windows. Technology had transformed the market faster than national codes could incorporate the new standards.
The building envelope is one of the most critical features of an energy efficient home. Heating and cooling account for 50% to 70% of the total energy used in the average American home, in which air leakage can be a significant cause of energy waste.
Insulation is a key element for a more comfortable and energy efficient home. It is important to have a continuous boundary of insulation between the conditioned, indoor spaces and the unconditioned, outdoor spaces. This boundary is referred to as the “building envelope” and consists of the walls, floor, and ceiling or roof and it provides the thermal barrier between the indoor and outdoor environment. Insulating ceilings, walls, and floors decreases the heating or cooling needed by providing an effective resistance to the flow of heat.