What is the “HERS” Rating System?
Facing the need for a more accurate metric to rate home energy efficiency, in 2006 the HERS (Home Energy Rating System) Index was established by the Residential Energy Services Network (RESNET) and is an integral part of the Energy Star Homes rating index. In fact, to become an Energy Star Home, the home must achieve a HERS score of 85 or less. Each decrease in the HERS Index by one point, corresponds to a 1% reduction in energy consumption compared to the semi-fictitious HERS reference home. For example, a home with an index of 70 uses 30% less energy than a home of the same size and shape build to minimum code standards.
The HERS index rates building envelope, lighting and appliances. The scoring system doesn’t measure actual energy usage, and it’s conservative-neutral, meaning it doesn’t take your usage habits into consideration. The energy savings are attributed to items like construction materials and solar systems but not to home size. Thus, the rating system is relative; a 3,000 square foot home with a rating of 100 typically will use more energy than the same size home with a rating of 50 (the lower number, the better).
Before any rating systems were established, assessments of a home’s energy efficiency were very subjective and based on building specifications such as, “There’s six inches of insulation in the walls and twelve inches in the ceiling.” Trying to quantify those specs into useful ratings was an impossible and often frustrating task for both builders and home buyers shopping for high efficiency homes and especially for net zero construction in Vermont.
The Vermont Home Energy Score
According to Efficiency Vermont, Vermont has taken the very good HERS rating system and made it easier to understand. The new system is called the Vermont Home Energy Score (VHES). Vermont is seeking to make net zero construction in Vermont the standard for new construction by 2030, so having an easy to understand and future-proof rating system is important. While Vermont, with its focus on home energy efficiency is an early adopter, the Department of Energy (DOE) is seeking to expand participation nationally.
What Does This Mean for Me?
Utility Bill Savings. Obviously, the big win is saving home energy costs. For net zero construction in Vermont, the scoring system is vital. Taking Vermont weather and home occupancy into consideration, the VHES estimates energy usage based on a points system. The lower the score the better, with zero indicating achievement of ‘net zero’.
Resale Value. Homes with a lower HERS score are a huge asset for real estate agents and sellers alike. In some markets, the MLS has added a line item to standard listing forms displaying the HERS index. Energy efficient homes, especially net zero construction in Vermont homes, offer a lifetime of savings that demonstrate the home’s extra value.
Construction Costs. Builders and clients work closely to select the most cost-effective efficiency products and practices. A net zero home is always more than the sum of its parts. And successful building always involves a highly integrated work process.