Since 2000 the technical basis for the HERS® calculation has been the Normalized Modified End Use Loads Method. Standard ANSI/RESNET/ICC 301-2014 and the Energy Rating Index compliance option of the 2015 International Energy Conservation Standard are both based on this calculation method. To date over 1.7 million homes have been HERS® rated and issued a HERS® Index score based on the method. Philip Fairey provided a primer on the Method at the 2016 RESNET Building Performance Conference. The Florida Solar Energy Center has published a detailed research report on development the methodology, which is posted at The HERS® Rating Method and the Derivation of the Normalized Modified Loads Method There has been discussion as to whether RESNET should consider another metric as the basis for calculating the HERS® Index. RESNET’s Standard Development Committee (SDC) 300 Calculations Subcommittee researched available options, identified pros and cons for each alternative and submitted a report to the SDC 300 Chair. That effort did not result in a consensus recommendation for change. One popular proposal is an energy cost-based method but a major concern with this approach is the influence of competing energy industries. To investigate this concern further the RESNET Standards Management Board (SMB) has directed the SDC 300 to establish a Cost Based HERS® Index Task Group. Previously the Edison Electric Institute submitted a proposed standard amendment that focused on a cost-based Index calculation method. The proposed amendment was not deemed critical by the SMB and will be considered in the next scheduled update of the RESNET Standards. The task group will explore whether a consensus can be achieved on a cost-based index concept and, if so, draft a work-plan for its development. At this time, this is a preliminary feasibility study and not a standard development effort. The issue needs to be very carefully considered because a change could result in significant changes in HERS® Index scores. This task group is chaired by Jerry Phelan of Covestro with task group members as follows: Martha Brook, California Energy Commission Craig Drumheller, National Association of Home Builders Philip Fairey, Florida Solar Energy Center Neil Leslie, American Gas Research Institute Vrushali Mendon, Pacific Northwest National Laboratory Steve Rosenstock, Edison Electric Institute RESNET will also be forming an advisory group that will review and provide comments on the preliminary feasibility study to the task group and the RESNET SDC 300 before being adopted. If you are interested in applying for the advisory group please e-mail Steve Baden at sbaden@resnet.us
