A document used in engineering and construction, typically a spreadsheet or specialized software form, systematically determines the energy demands of a building or space. This involves calculating heating and cooling requirements based on factors such as building materials, insulation, window area, climate, and occupancy. For example, such a document might estimate the British Thermal Units (BTUs) needed to heat a home in a specific climate zone based on its square footage and construction features.
Accurate estimations of energy needs are critical for proper HVAC system sizing. Undersized systems result in inadequate heating or cooling, while oversized systems lead to energy waste and inefficient operation. Historically, these estimations were performed manually, a tedious and potentially error-prone process. Modern tools have streamlined this process, allowing for more precise calculations and incorporating more complex variables like solar heat gain and ventilation requirements. Proper sizing ultimately contributes to lower operating costs, improved occupant comfort, and reduced environmental impact.