New DOE R&D Roadmap Looks to Next-Generation Insulating Capability
Given the enormous amount of U.S. energy consumption attributed to buildings, the 2013 State of the Union address announced a new goal of reducing energy losses in buildings by 50 percent over the next 20 years. The latest Department of Energy Research & Development report, “Windows and Building Envelope Research and Development Roadmap,” provides guidance to help make this happen.
It encompasses a number of futuristic technologies, primarily:
- Highly insulating windows rated R-5 or better (U-factor of 0.20 or less)
- Dynamic windows and window films demonstrating marked SHGC improvement
- Visible light redirection to reduce lighting energy use
- Building envelope insulating material rated at more than R-12 per inch
- Air-sealing technologies that simultaneously regulate heat, air and moisture flow.
For each of these technologies, the focus is on improving performance as well as developing specific strategies to reduce installed costs and consequently increase the likelihood of mass-market adoption.
EMERGING WINDOWS TECHNOLOGIES
The highest R&D priority is a costeffective, highly insulating window with reduced installation cost. In the residential sector, the goal is an R-10
window with less than $6 per-squarefoot installed cost premium over the 2010 installed base of windows (averaging R-1.61). In the commercial sector, the target is an R-7 window with less than $3 per-square-foot installed cost premium over the 2010 installed base (R-1.86).
To accomplish this, performance improvement is needed in both glazing and framing. High-performance glazing such as Vacuum Insulated Glazing—with proven edge seal durability and next-generation low-E coatings—are likely players.
Other emerging technologies include:
- Dynamic windows: Glazing materials and low-E coatings that selectively control the spectral aspect of radiation are now commonplace. It is also possible to design glass that changes state depending on properties such as an applied electric current (electrochromic, a.k.a. “switchable glazing”) or glass temperature (thermochromic).
- Visible light redirection: Existing daylighting approaches, such as light louvers and tubular daylighting devices, have great potential to save energy in the commercial sector when integrated with lighting controls. The target is to reduce lighting energy by 50 percent for a 50-foot floor plate, at an installed cost premium of less than $5 per square foot over a typical window/blind installation (including the cost of lighting controls).
- Building envelope technologies: Improving overall building energy performance will require R&D to produce cost-effective building envelope insulating materials. One example is Vacuum Insulated Panels, which have an R-value three times higher than fibrous batt insulation at onethird the thickness.
- Air-sealing systems: Currently there is no single existing air-sealing technology capable of simultaneously controlling heat, air and moisture. New research is needed on how these elements are interrelated and how to best regulate them to achieve, for residences, less than one wholebuilding air change per hour at a differential pressure of 50 pascals.
THE R&D AND EDUCATIONAL CHALLENGE
A substantial and sustained commitment to R&D that focuses on reducing installed cost and increasing performance is essential to realizing the energy-saving promise of nextgeneration window and building envelope technologies. This level of R&D will require long-term, high-risk research and public-private collaborations prioritized on the basis of energy-saving potential.
There also is an educational element besides hardcore technical R&D. In this area, BTO plans innovative measures such as real-time infrared displays through a program similar to Google Street View that shows whole building energy use and identifies how much energy is being lost through windows.
It’s going to get interesting.
One aspect of all this in which AAMA can help, in addition to encouraging collaborative R&D, is in its established role as an ANSIrecognized developer of performance standards to serve as a basis for code acceptance and product purchase evaluation. In the end, it’s the homeowners who will decide the R&D winners and losers.