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It is important to understand that the Home Energy Rating System (HERS®), based on ANSI Resnet Standard 301-2014, is the existing compliance method of the Energy Rating Index (ERI). They are essentially two terms describing the same thing, with HERS being a proprietary acronym created by the Residential Energy Services Network (RESNET), and ERI being the term used for the Energy Rating Index included within the Florida Energy Code language.
When building a new home there are genuine advantages to having a HERS score calculated. Such as confirming to prospective buyers the benefits of a well built, high performing house. The value of lower utility costs, higher comfort levels and air quality. This score can easily transfer over to the ERI compliance documentation for permitting if the projected score is within the range required by the Florida Energy Code.
What is the ERI Performance Path?
The Energy Rating Index performance path gives builders the flexibility to choose from yet another option for complying with the Florida Energy Code. In addition to the prescriptive, UA and simulated performance alternatives, the ERI score allows builders the option of meeting target scores through a wide range of materials, methods and performance options. However, builders should keep in mind that although the ERI offers flexibility in terms of materials and applications, there are still mandatory requirements such as retaining the minimum insulation and envelope levels required by the 2009 IECC.
What is an ERI Score?
The ERI is a numerical score where 100 is equivalent to the 2006 IECC and 0 is equivalent to a net-zero home. The ERI uses the HERS methodology for computing the score but sets limits on how high the score can be in order to meet the requirements of the energy code. For example, in Florida's climate zones one and two, the score must be 58 or lower. The index scores were determined using a modeling method in each of the climate zones and based on an analysis performed by the Florida Solar Energy Center.
What is evaluated in determining a building's ERI score?
The ERI path introduces many variables not currently included in the other compliance pathways. Items such as high efficiency heating, cooling and water heating equipment are evaluated. Credit is given for high efficiency appliances. Envelope tightness and duct sealing measures can be calculated and accounted for. Quality insulation and sealing installation techniques are verified and graded. Many aspects of how the building is constructed and the materials and equipment chosen are evaluated and given an energy rating. All of these aspects come together through a computer simulated energy model and third party inspections to determine the rating a building will achieve.
How are HERS Raters certified and what level of quality assurance is built into the ERI pathway?
Resnet is the governing and standard setting body within the HERS rating world. HERS Raters are certified RESNET Raters after studying building performance coursework and having their knowledge verified through field and online testing. Raters must demonstrate compliance with ethical standards and continual professional education. All raters must have their work periodically verified by a Quality Assurance Provider in order to uphold the standards of ethics and accuracy within the field of energy ratings.
How do I show compliance to the Florida Energy Code when utilizing the ERI pathway?
By hiring a Resnet Certified Energy Rater to document, inspect and verify the materials and installation methods utilized during the construction of your building, an energy rating can be performed. For pre-build permitting documentation, the ERI score is calculated via building energy modeling using the building plans and specifications and the appropriate software. The score is then verified through third party inspections and envelope testing post-build.
Who provides ERI scores and third party verification?
Energy By Design is a residential energy services company specializing in Florida Energy Code compliance documentation and 3rd party verification. We have the certifications needed to perform ERI calculations and the knowledge to help you, the builder, architect or homeowner, navigate through the requirements set by the Florida Energy Code.
Give us a call today!
Eric Goodwell
Energy By Design
(407) 450-0295