The primary purpose of this paper is to compare annual heating and cooling loads of buildingscontaining different amounts of mass. The effect of different amounts of resistanceinsulation combined with the mass was included in one of the study series.It is important to know that in each study series, the assumed values for input such asthermostat set-points, ground temperatures, air changes, absorptive factors, lighting andoccupants remain identical when comparing loads for light construction with loads for heavyconstruction. If the assumptions were different than shown, the results would reflectequally for both constructions, and therefore have very little if any effect on thedifference between loads.