HVAC power density: an alternate path to efficiency.

Identifying the impact of energy-efficient building envelopes, internal equipment, lighting and HVAC systems is difficult given the complexity of modern installations. The recommended practice of conducting a building energy simulation may not be an affordable option for many projects. The use of HVAC system power density guidelines is an alternative that does not require much beyond the level of effort required for conventional design. It also directly identifies the impact of all system components upon the net efficiency of the building HVAC system. The concept is not proposed as a replacement for Standard 90.1, which is frequently used for code compliance. HVAC power densities are intended to provide a set of indicators to identify "good, better, best" building efficiency levels for a variety of building types and climates.