Under the proposed code, new homes more than 11,000 square feet in size would be required to have a Home Energy Ratings System (HERS) score of zero, effectively meaning all the home’s energy must be produced by solar power or other renewable energy systems.
Smaller new homes would need to comply via a sliding scale of the HERS scoring system based on the amount of their energy used. The smaller a home, the more energy it’s permitted to use per square foot.
For those not aware of how the HERS system works, here’s a brief summary with links for more information
The HERS Index
The HERS Index is a scoring system established by the Residential Energy Services Network (RESNET) in which a home built to the specifications of the HERS Reference Home (based on the 2006 International Energy Conservation Code) scores a HERS Index of 100, while a net zero energy home scores a HERS Index of 0. The lower a home’s HERS Index, the more energy efficient it is in comparison to the HERS Reference Home.
Each 1-point decrease in the HERS Index corresponds to a 1% reduction in energy consumption compared to the HERS Reference Home. Thus a home with a HERS Index of 85 is 15% more energy efficient than the HERS Reference Home and a home with a HERS Index of 80 is 20% more energy efficient.
U.S. Department of Energy’s EnergySmart Home Scale
The EnergySmart Home Scale (E-Scale) was developed by the U.S. Department of Energy (DOE) for the National Builders Challenge. The E-Scale is based on RESNET’s HERS Index. For more information view a brief E-Scale Video .
DOE has developed an E-Scale Interactive Tool to compare estimated cost and energy savings of new and existing homes. To chart the savings how improving the E-Scale score, launch the E-Scale Interactive Tool .
Choosing a Rater
As in any trade, all raters are not the same. Raters have different experience, training and skills. You should not select a rater based solely on price. The following are issues to consider when choosing a home energy rater to work with:
- Find out what are the basic services the rater provides. RESNET has adopted a Rating Standards of Practice to define this.
- Determine what training and experience the rater requires to meet your needs. In addition to receiving a rating score, will you require design assistance, HVAC sizing calculations, or construction crew training? Be sure you know that the rater’s skills meet your needs.
- Make sure that your rater carries proper insurance coverage. RESNET has arranged to provide affordable and comprehensive general liability and professional liability insurance coverage for raters. Make sure that the rater you hire is properly insured.