What is an energy efficient building

Proposed regulations in Brazil call for minimum energy efficiencies in building design and appliance manufacture. These regulations are expected to translate into lower operating costs for the occupants, reduced energy demand for the utilities, and potentially lower carbon emissions for the country. The concept of “energy efficient” buildings has immediate implications on regulations, economics, energy demand, and the environment. A definition is also needed to compare building energy performance or to assess absolute energy efficiency. We propose three criteria for an energy efficient building: 1) the building must be equipped with efficient equipment and materials appropriate for the location and conditions; 2) the building must provide amenities and services appropriate to the building’s intended use; and 3) the building must be operated in such a manner as to have a low energy use compared to other, similar buildings. An efficient building must, at a minimum, be above average in all three aspects. When setting minimum efficiency standards, a definition of energy efficiency based on minimum life cycle costs is likely to result in much stricter standards—and greater energy savings—than a strategy based on eliminating the least efficient units.