Builders who achieve Energy Star for Homes certification have always paid attention to the elements needed for a high-performance home. They start with the design, build an airtight home and use the right insulation and air barrier, then upgrade it with energy-efficient doors, windows, appliances, and systems.
As of January 1, 2025, the Energy Star for Homes certification has been given its own upgrade. For builders that want to be eligible for the IRA 45L tax credit, all new homes1 acquired after the first of the year must meet the new standards of Energy Star Single-Family New Homes Version 3.2, which requires insulation levels aligning with 2021 International Energy Conservation Code (IECC).
Two key updates include:
Compliance Simplified with Styrofoam™ Insulation
One of the easiest ways to adapt to the higher Energy Star for Homes certification standards is to install continuous insulation, like DuPont™ Styrofoam™ Brand XPS Insulation. Installing DuPont™ Styrofoam™ Brand XPS on the exterior of the wall helps both reduce heat losses from conduction through the wood framing and helps keep the interior sheathing above the dew point to reduce the chances of internal condensation.
Styrofoam™ Brand XPS Insulation is closed cell insulation, which absorbs less water over time than EPS foam insulation. Absorbed water can cause damage in freeze/thaw conditions, which makes Styrofoam™ Brand XPS a particularly good choice for cold climates. It maintains a higher R-value than EPS insulation, particularly when moisture from humidity or storms is present.
UA Calculator for Ultimate Accuracy
Determining how much insulation is needed for any particular project can be complex, especially as code requirements change. Many builders rely on the prescriptive method, which follows strict tables and guidelines, or they opt for simulations or Energy Ratings Index approaches that require a whole-house evaluation.
An alternative method, “UA” can be used to focus on thermal efficiency of the building envelope to calculate insulation needs. A “U value” is the inverse of R-value and measures the amount of heat flow through a material. A UA calculator measures U-value times area for the total home wall area; designing a home with a UA value below the code required UA value helps meet the energy requirements.
DuPont offers a proprietary UA calculator for Energy Star builders that provides customized information about insulation requirements. In addition, experts at DuPont work with builders using the calculator to offer suggestions about trade-offs that can be made to achieve or exceed efficiency requirements and new products.
Styrofoam™ Brand XPS Installation Guidelines
Since Styrofoam is lightweight, installation can be quick and easy. The product can be stored outside on a construction site, if necessary, since it’s not affected by water. The material can be easily cut with regular hand tools such as a utility knife.
Installing Styrofoam™ Brand XPS doesn’t require any major framing changes to your project. These quick videos offer more insight into the installation process.
Want more information about StyrofoamTM Brand XPS? Contact DuPont today and learn about how they can help with thermal performance.
1Exceptions are California and Hawaii, which require California v3.3 and Pacific v3 respectively for eligibility for 45L.
New Chemistry Improves Styrofoam™ Brand XPS’s Sustainability
Using Styrofoam™ Brand XPS Insulation provides a high level of energy efficiency to help you meet new Energy Star requirements. In addition, DuPont has worked hard to fulfill its own internal sustainability goals. In 2019, DuPont began the process of reformulating Styrofoam™ Brand XPS Insulation to offer a low global warming potential (GWP) version.
Since the end of 2023, all sites in North America that manufacture Styrofoam™ Brand XPS have produced a low GWP formulation. Builders will notice that the reformulated version of the product is now grey rather than the familiar white of the former version.
Reformulated Styrofoam™ Brand XPS has both a published environmental product declaration (EPD) and an embodied carbon/lifecycle optimization assessment that demonstrates the product achieved a 94% reduction in embodied carbon relative to the previous formulation. The new version uses 20% pre-consumer recycled content on average as certified by UL Environment. In addition, all Styrofoam™ Brand XPS products are produced using 100% renewable electricity.