The ANSI/RESNET/International Code Council Standard 301 incorporates new water heating efficiency calculations, including Drain Water Heat Recovery (DWHR) in calculating a home’s HERS® Index Score. RESNET accredited HERS® Rating Software programs were to incorporate the new standard in their software tools beginning on January 1, 2016. As a result of inconsistencies in incorporating the new standard, the RESNET Board of Directors moved the date that HERS® Raters must use the revised software programs to July 1, 2016. Despite this delay, HERS® Raters can still credit DWHR systems through the Innovative Design Request that RESNET has adopted to calculate energy savings for DWHR systems and provide an appropriate HERS® Index score credit where these systems are properly installed in homes. The RESNET Drain Water Heat Recovery Innovative Design Request will remain in effect until the revised HERS® rating software tools go into effect. For information on how to incorporate DWHR systems into a HERS® rating along with an example of completed determination of DWHR Systems for HERS® Index credits go to RESNET Innovative Design Request on Drain Water Recovery
