Prescriptive vs Performance Path – IECC Energy Code Compliance:
Let’s face it, compliance with the ever-changing IECC Energy Codes is like tracking a moving target. Each municipality has its own code requirements and amendments, and understanding these is tough. There are typically two main pathways for compliance – Prescriptive Path or Performance Path.
The Perscriptive Path presents a specific list of features and items that have to be met for compliance, with no deviations allowed. At first look, the Prescriptive Path appears to be the easier and simpler route. But the rigid list of mandatory items offers very little flexibility in design approach or material selection to meet the project needs. Additionally, you, as the contractor, architect or designer need to have an indepth understanding of each municipality’s requirements and amendments.
The Performance Path offers the designer or builder the most flexibility in meeting the energy code requirements. A HERS Rater is involved in the project from the early design stage to model the energy performance of the home and to determine compliance. This pathway allows for optimal design innovation and integration of energy-efficient technologies. It is often perceived as a more expensive option compared to the Prescriptive Path. However, design teams often prefer the Performance Path because it allows them to evaluate various combinations of design strategies, components, and technologies, until they reach a solution that provides the greatest energy savings for the lowest overall cost, which is usually less than following the Prescriptive Path. Additionally, you can rely on the HERS Rater to understand the local requirements, leaving you more time to focus on design and construction.