ABSTRACT
A recently developed 3-dimensional earth contact simulation program that operates as a subroutine of the EnergyPlus whole building energy simulation program was used to evaluate the energy performance and cost-effectiveness of retrofit slab-on-grade (SOG) foundation insulation. An optimized retrofit insulation design utilizing hydro-vacuum excavation was developed that generated 8.4 % larger metered (or site) energy savings at a $428 lower cost than the IECC 2012 requirement in a Minneapolis, MN climate for a 400 ft2 test building. The energy performance and cost effectiveness of single and multi-family buildings was assessed for climate Zones 4 – 7. With reference to the Building America B10 benchmark, the highest site energy savings of 5 % was realized for a single family home in Duluth, MN, and the lowest savings of 1.4 % for a 4-unit townhouse in Richmond, VA. SOG foundation insulation retrofit simple paybacks ranged from 18 to 47 years. Thus it is likely that larger energy savings of 10% or more with concomitantly reduced simple paybacks can only be realized in well-insulated buildings.
Author notes
Program Director and Senior Research Associate, Energy Systems Design Program, University of Minnesota, and Principal, Lofrango Engineering.
Senior Research Fellow, Center for Sustainable Building Research, University of Minnesota.
