The EcoSmart™ Stud exterior wall system section of the Build Series will be divided into four parts: Cost and complexity, Insulation, Resilience, and Embodied carbon. First, we’ll delve into the cost and complexity, the primary concerns of most builders. We’ll explore the total cost of upgrades for the build and then move on to the other three parts of the EcoSmart™ Stud wall system that set it apart in the construction industry, offering a simpler and more straightforward approach.

The Energy Star Zero Energy Ready Home (ZERH) exterior wall requirement is the most expensive part of this 1420 sq ft rambler build here in Minnesota. In fact, it’s why Minnesota is still using the equivalent of the 2009 National Energy Code.

The local Builders Association has successfully lobbied for over 12 years that Continuous Insulation (CI) exterior walls introduced in the 2012 National Energy Code of R13+R10 CI and R20+R5 CI were to complex and expensive compared to the standard 2×6 framed walls with R-20 chamber insulation. They put the upgrade cost of the CI exterior walls at above $10,000 for the average 2800 sq ft new home. This also matches what we have calculated for CI exterior walls. The EcoSmart™ Stud was developed to solve this cost and complexity problem. The building community needs a more straightforward, less expensive solution than currently available to accomplish the requirements of the new Energy Codes for exterior walls.

For this Energy Star ZERH build, the exterior wall must meet the 2021/2024 National Energy Code requirement of U-0.45 (R-22.2) for the exterior wall. For this 1420 sq ft rambler style home build, we are framing 24″ on center, which requires fewer EcoSmart™ Studs than framing 16″ on center. The EcoSmart™ Stud upgrade cost over solid 2×6-104 5/8 framing studs is $4.10 per stud. For 235 EcoSmart™ Studs the extra Cost is $963.50. The 24″ on center framing with flash and fill insulation gives the EcoSmart™ Stud exterior wall a U-0.038 (R-26.38) rating. Well below the required U-0.045 or above (R-22.2).

The Flash and Fill insulation estimate is for 1.5″ of 2-pound closed cell spray foam back-filled with 4″ of blown-in cellulose. No vapor barrier, sealant caulk, or electrical vapor boxes are needed for the EcoSmart™ Stud wall system. The Vapor barrier is the 1.5″ of 2-lb. closed cell spray foam applied to the sheathing that spreads out through the EcoSmart™ Studs. The upgrade cost is about $505 for the flash and fill insulation vs. R-20 fiberglass batt insulation.

The EcoSmart™ Stud exterior wall system upgrade cost for this smaller 1420 sq ft build here in Minnesota is about $1,468.50. Compared to the estimated cost upgrade of $6,800 for the National Energy Code 20+5 CI wall system, the EcoSmart™ Stud exterior wall system is about 78.5% less expensive than the National Energy Code CI wall system, providing a significant cost-saving opportunity for builders.

A significant portion of the savings is due to the efficiency of the EcoSmart™ Stud wall system, which eliminates what we have termed the ‘Extra Step Conundrum.’ The CI style of wall insulation often requires numerous additional ‘details’ or ‘steps’ that consume extra material and labor during installation of the CI insulation, windows, doors, siding, and soffits. In contrast, the EcoSmart™ Stud wall system is a single-part swap of the solid framing stud and changing insulation style. No extra steps or materials making construction more efficient.  See our PDF the “Value Added Checklist” in the resource section for a side-by-side comparison.

Now that we have all the cost upgrade details for the different required elements, we are reviewing the total cost upgrades to build this 1420 sq ft Energy Star ZERH rambler, which is next!