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Energy Code Update

How Energy Code Evolutions Will Impact Residential Fenestration

The National Glass Association’s Thirsty Thursday webinar on June 18, presented by Tom Culp, Birch Point Consulting and NGA technical codes consultant, dissected some of the upcoming energy code evolutions in 2020 on a national and regional level.

International Energy Conservation Code

The IECC is the primary energy code for residential building in the U.S., with the next update coming out in 2021. The fenestration industry likely will not be significantly affected by the changes, in large part “because we negotiated agreements on key items, so they were on the consent agenda and not subject to vote,” Culp explained.

Items up for vote before the 2021 adoption shouldn’t affect a standard Energy Star-rated window, but will reduce flexibility for non-standard products, said Culp, including confusing overlapping “backstops” on windows when using trade-off paths. Expect small changes in prescriptive U-factors, such as U-0.30 in zones 3-8 and allowances up to 0.32 in windborne debris regions or in areas with elevations higher than 4,000 feet, to allow for more flexibility in products.

Voting changes also introduced a new maximum solar heat gain coefficient in zone 5. There also is indirect positive pressure for fourth surface low-E and/or triple glazing in the next IECC.

California’s Title 24

Work on California’s Title 24 2022 edition is underway. Stakeholders are in a series of meetings now and working on case reports with the goal to enter the rulemaking phase next year.

Although no official proposals are on the table, Culp pointed to two residential fenestration points:

  • No new changes for windows will be enacted for single-family homes, in large part because the 2019 edition updated to a U-factor of 0.30 and solar heat gain coefficient of 0.23.
  • Multifamily might all fall under one standard, regardless of the size. Challenges revolve around how to account for windows in low-rise vs. high-rise, considering different construction, structural requirements and product types. Culp says to expect a draft case report for public review this fall.

He also said that some builders in California are putting in triple-glazed windows so they can lighten up on what Culp described as “dramatic changes” to wall insulation requirements.

Canada’s Energy Codes

Canada is also being what Culp described as “very aggressive about energy efficiency” and is finalizing the 2020 National Energy Code for Canada for Buildings. The country is committed to a net-zero energy ready model building code by 2030. Some provinces already use their own codes, such as the step codes in British Columbia and zero emissions building plan in Vancouver. Among other requirements, the code proposes reducing the U-factor in all zones, even beyond what ASHRAE 90.1 and the 2021 IECC requires. Culp says this “aggressive” proposals is achievable, but only for fixed fenestration; it’s problematic for operable windows.

Visit to read about four energy code updates that will affect the commercial construction industry.

4 Energy Code Updates


3 Updates to the Green Building Standard for Fenestration

As part of the Window & Door Manufacturers Association’s annual Technical and Manufacturing Conference hosted online in June, Michelle Foster, VP, sustainability for Home Innovation Research Labs, provided an update on the 2020 National Green Building Standard. For those unfamiliar, the NGBS is a voluntary above code green certification program and is part of the ICC suite of I Codes. It offers alternative compliance for the IgCC.  

Registration for the latest 2020 NGBS opened in mid-April and includes many revisions, including an expanded scope and definition of “residential” as well as entirely new updates for homes, townhouses and duplexes. Foster stressed that the program offers rigor and flexibility. “While it’s rigorous in compliance,” she said, “there are a lot of ways [for builders] to gain points. They have more choices depending on the needs of the building.” 

There were three big changes or new inclusions most relevant to the residential fenestration space:  

01  Chapter 6, Resource Efficiency, contains significant changes and, among other new attributes, new sections on product declarations and resilient construction. Points are awarded for design and construction practices that “enhance the resilience and durability of the structure.”   

02 Chapter 11, which wholly contains all of the certification requirements for remodeling projects, now provides for both a prescriptive and performance path to certification. This, according to WDMA conference participants, may open up new opportunities for fenestration manufacturers.  

03 Chapter 12 of the NGBS offers a new certification level exclusively for single-family homes, townhomes and duplexes. The certification is binary; there are not multiple levels as there are for other NGBS certifications, but rather a project is certified or isn’t. All of the practices are mandatory and, according to Foster, focus on the most impactful green measures, which she defined in the categories of energy and water efficiency, moisture and mold management, and indoor environmental quality.  

A handout from the session noted that window and door products can contribute toward homes and multifamily buildings meeting air leakage and UA requirements in the Energy Efficiency chapter. Also, WDMA noted that it is updating product category rules that will apply to some of the requirements outlined in Chapter 6.  

For more information on the 2020 NGBS, visit and/or go to


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Laurie Cowin

Laurie Cowin is editor of Window + Door. Contact her at


Emily Katy Thompson

Emily Kay Thompson

Emily Kay Thompson is associate publisher of Window + Door,, and W+Dweekly. Contact her at