Commercial Replacement & Attachment Window Solutions

CalMTA has developed Advancement Plans for six market transformation ideas. These plans describe the research and investigation that would be needed to complete an eventual full Market Transformation Initiative (MTI) Plan to determine a market transformation (MT) theory and scope for future implementation. Below is a summary of the market transformation idea for Commercial Replacement & Attachment Window Solutions (CRAWS), currently in Phase II: Program Development.

Sector: Commercial 

Product Definition: Single-pane replacement (SPR) utilizes the unique properties of vacuum-insulated glass (VIG) to increase uptake and investment in commercial retrofits, especially for buildings with single pane glass. SPR involves the use of ultra-high-performance VIG with a nominal thickness of ¼” to ½” and an insulating R-Value of R-10 to R-15. VIG replaces a ¼” single-pane glass in existing commercial frames and improves thermal performance of the glass by a factor of 5-10x. SPR with VIG provides fuel neutral savings and reduces HVAC load by as much as 40%. The reduced load then provides an easier pathway for commercial building owners to convert from conventional HVAC systems to heat pump systems at reduced electrical load.    

Alternatives to VIG include commercial secondary windows (CSW). CSWs attach to the interior or exterior of the existing window, creating an additional insulating layer and offering options for solar control via low-E films. CSWs improve room comfort less than VIG replacements, but still significantly reduce HVAC load, are a more mature technology, less expensive and, like VIG replacements, can be installed without opening the façade or disrupting occupants. 

Preliminary Market Transformation Theory: Windows are responsible for about 10% of energy use in buildings and influence end uses that comprise 40% of building energy use¹. The target market for this potential MTI represents over 75% of California’s 3.2 million existing commercial buildings built between 1965 and 2000. Many of these buildings have inefficient, single pane glass. Yet replacing windows is very expensive and involves extensive tenant disruptions; thus, single-pane windows are replaced at a rate of only 1% per year.   

This potential MTI would take advantage of growing awareness that poor performing commercial windows need to be addressed if existing buildings are to be successfully decarbonized. A key leverage point would be the rise of commercial building performance standards that compel building owners to reduce their buildings’ energy use, or face penalties. CalMTA would also leverage aggregators in the commercial building market to build market awareness on VIG’s and CSWs’ extensive benefits and business case. A third strategy would be to work with the National Fenestration Rating Council (NFRC) and other industry partners to build the needed testing, certification, and documentation systems for VIG. We would also engage local utility programs to offer incentives to help bring down the cost in the near-term. 

Read the advancement plan

[1] Partnership for Advanced Window Solutions at U.S. Department of Energy