The Standards Project Committee (SPC) for Standard 90.2, Energy Efficient Design of New Low-Rise Residential Buildings, has developed simplified procedures to estimate seasonal heating and cooling load savings for all envelope components, above and below grade, of single-family and multi-family housing. The general form of the simplified load-savings equations is to predict a load savings as a function of a change in U-factors and a single weather variable, HDD65 for heating and CDH74 for cooling. All of the equations are linear, and their slopes were called load factors. Another application of the load-savings equations was the development of a simplified trade-off procedure for all of the envelope components. One advantage of these equations is the capability to trade off opaque components with glazing shading coefficients and orientations, as well as the traditional glazing U-factor. This simplified capability did not exist in previous versions of the standard.

KEYWORDS: domestic, housing, calculating, heat load, cooling load, energy conservation, glazing, windows, orientation, shades, ceilings, walls, floors, doors, factors