HERS Index - Energy Modeling
JKP Energy Inspections uses the RESNET approved energy analysis software Ekotrope to calculate a Home Energy Rate Score (HERS) for homes.
Home Energy Rating System (HERS Rating) The HERS Index is a scoring system that “rates” a home’s energy usage compared to a code minimum reference home. The details that determine the final HERS score are extracted from the building plans and building performance testing and inspections. The lower a home’s HERS Index, the more energy efficient it is. A HERS Index of 100, would indicate the home complies with the minimum code requirements while a net zero energy home would score a HERS Index of 0. Each 1-point decrease in the HERS Index corresponds to a 1% reduction in energy consumption compared to the HERS Reference Home. For homes to comply with the new 2012 IECC Energy code a HERS index of 65 or less is required.
The software takes into account features of the home to calculate the HERS including:
- Exterior wall framing and insulation
- Mechanical Equipment
- Attic insulation
- Lights & appliances
- Ventilation
- Windows & doors
- etc.
We can also use energy modeling to calculate:
- Heating & cooling loads
- Utility costs
- Energy use
- City code compliance (IECC)
- Other energy program compliance
Energy Modeling
How does it work?
Plans & Specs
Builder/architect provides plans & specs for all floor plans for community or house.
This includes:
Architectural plans
Mechanical plans
Roof & Elevations
Specs: Insulation, window, door, model #’s etc.
Software
Once we gather all the necessary information for the HERS rating, we enter this into the energy modeling software Ekotrope.
The software interprets all of the information provided and gives the homes a HERS score and if the plan passes any city codes or other energy programs such as Energy Star.
More info on Ekotrope can be found at: https://www.ekotrope.com/hers-ratings
Worst Case Scenario
Based on RESNET Standards, since we sample homes, we must preform a worst-case analysis on each home plan in a sample set.
A Worst-case analysis is a home energy rating from a specified home plan for which the minimum rated features of the home are configured to provide the poorest energy performance of the home (i.e. the largest HERS Index) when four ordinal home orientations and the least energy efficient minimum rated features for the specified home plan are considered by the Rating.
That worst-case HERS rating is then used for all homes with that floor plan within that community.
Definitions & Links:
- RESNET Standards
- Sampling - An application of the Home Energy Rating process whereby fewer than 100% of a builder’s new homes are randomly inspected and tested in order to evaluate compliance with a set of threshold specifications.
- Sample Set - A specific group of homes from which one or more individual homes are randomly selected for sampling controls.
Certificates
The HERS certificate is printed and sent to the customer!