Oft Forgotten Fenestration Should be an Energy Efficiency Priority

January 27, 2016 By Carl Weinschenk

doorsHow soundly fenestration – the windows, doors and other elements that are inserted into buildings – is handled goes a long way toward determining energy efficiency and costs.

This week, the American Architectural Manufacturers Association (AAMA) updated its method of determining thermal performance of fenestration systems in commercial buildings. The document – “Standard Practice for Determining the Thermal Performance Characteristics of Fenestration Systems in Commercial Buildings” (AAMA 507-15) — was the first update to the procedures since 2012, according to the organization.

Dean Lewis, the AAMA’s Technical Manager for Training and Education, indicted the document was not dramatic. “There are no changes to the required procedures,” he told Energy Manager Today. “Referenced standards were updated, definitions were moved to the AAMA Glossary, the previous Certificate of Compliance was re-named Fenestration Product Rating Certificate, and is now provided in both IP and SI versions. Information on Types of Framing Systems was moved from Section 5 to Appendix A of the document.”

While the changes don’t seem to be major – Lewis says that the process will be easier to use and reference, but the procedures will be “totally familiar” — it is an opportunity to look at this vital energy issue. The press release on the announcement indicates precisely why building owners and facility managers must be up to speed on fenestration:

Fenestration impacts building energy use through four basic mechanisms: thermal heat transfer, solar heat gain, visible transmittance and air leakage. Condensation resistance is considered not to affect energy use and is therefore not a concern of the building codes. However, CRF is an important thermal performance characteristic and is therefore included in this document.

To date, however, attention has been lacking, according to Lewis: “Fenestration has historically been the weak link in building envelope thermal efficiency. Energy use in commercial buildings is usually dominated by cooling loads. With their large expanses of glass, these structures are particularly vulnerable to the effects of Thermal Transmittance (U-Factor), Solar Heat Gain Coefficient (SHGC), Visible Transmittance (VT), and Air Leakage.”

There seems to be good news here for facility managers and building owners. Lewis’ point that fenestration has been running below the radar means that there almost certainly are relatively easy gains to be made by finally giving it full attention.

Last week, Window & Door’s Emily Kay Thompson wrote about what the fenestration industry expects in 2016. Color and multi-panel doors, she wrote, are the biggest items. The third prospective trend will be energy-related:

Finally, as expected, Energy Star-rated products reportedly accounted for more than a quarter of the products introduced in 2015 and 38 percent of planned product launches for this year. While only 7 percent of dealers ended up selling these lines in 2015, 21 percent of surveyed dealers plan to incorporate Energy Star-rated products in 2016.

This suggests that awareness is growing. It only makes sense: Punching a hole through a wall and installing a door or window is a sensitive operation that, if not done correctly, can result in money literally being thrown out the window. It’s an interesting item, since efficiency is only one of several important areas of concern. Windows and doors play a vital role in safety. Windows and doors must be easy to use and, of course, everything must be done stylishly.

Last spring, Construction + Design posted a long story that focuses on American Architectural Manufacturers Association’s new FenestrationMasters program. Two things are not surprising: Fenestration is becoming more complicated and energy issues are front and center:

New techniques for assessing energy performance can give Building Teams a leg up on the design process. The National Fenestration Rating Council’s (www.nfrc.org) new product certification program for commercial applications reduces the review of fenestration product energy performance to three key components and creates a library of those components that project designers and contractors can use to make selections. The NFRA process, called the Component Modeling Approach (CMA) Product Certification Program, lets you assess whole-product energy efficiency for custom systems designs with varied shapes, frame materials and depths, and glass materials.

Lewis pointed to five sources of more information for facilities managers, engineers, architects and others who are interested in fenestration requirements. They are AAMA 507-15; ASRAE/IES Energy Code for Commercial and High-Rise Residential Buildings; The Energy Code for Buildings Except Low-Rise Residential Buildings (ASHRAE/IESNA 90.1); the IBC International Building Code and the IECC International Energy Conservation Code.

 

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