Page 24 - CodeWatcher Summer 2017

HERS Index:

The Next Level

BY MIKE COLLIGNON

The following is an excerpt from a presentation Robby

Schwarz, principal and director of Builder Relations at

EnergyLogic, delivered at a recent RESNET conference.

HE HERS INDEX has been A Moving Target
a positive addition to the For all the upsides the HERS Index brings, it is under
home building industry constant scrutiny and refinement. This is logical, since the
on a number of levels. At a home building industry does not remain static. We need
minimum, it enables a builder innovation in our construction products and techniques;
to baseline the efficiency of therefore, our modeling programs need to accommodate
their houses. those advancements.
It also introduces additional The following items are aspects of the program that could
flexibility to the energy code use additional refinement:
through the Energy Rating ■ ■ Energy Optimization. Many builders are looking for the
Index (ERI) pathway that is HERS/ERI path to help them optimize their specification.
T largely based on the HERS “The simple fact is that the system cannot and should not be
Index and was originally adopted into the 2015 IECC. used to allocate a dollar per Index point,” says Schwarz. The
From that, builder resistance to energy code adoption has system is not linear because it uses a systems approach and
decreased (though to what degree depends on the jurisdiction analyzes the synergies between all components used to build
and the IECC edition that was adopted). the house. One upgrade will not always give you a specific
The Index boosts both design and product choice freedom number of Index points.
and brings the building and energy efficiency communities ■ ■ Very High Performance Homes. It's difficult to get below
together to debate the degree of energy efficiency (instead of a HERS 40 with a super-insulated home with a state-of-the-
whether or not we should be incorporating energy efficiency art mechanical system. Although there may be energy ben-
at all). efits, the HERS/ERI path stops allocating Index points due
But perhaps most important, the HERS Index offers a to diminishing returns. This poses a problem for builders
simple metric and corresponding marketing message that and designers of high performance homes such as Passive
the home buying public can understand, regardless of their Homes, which are gaining market share. “For example, if
comprehension of building science. you’re designing a Passive House, it is important to be able

24 CodeWatcher / Summer 2017 www.codewatcher.us