We love our windows — the views, the natural sunlight and the expanded visual space. New homes have more and more windows and then, we cover them up because we want privacy or the sunlight makes our indoor space too warm (or cold) … confusing?
There are home electronic systems that let you remotely turn on lights, raise the thermostat and open/close your window coverings. The problem is you have to remember to do this, which means finding your smart phone, the right application and it takes time.
What if your windows were smart enough to allow more or less light into your home, like light adjusting glasses and sunglasses? The window technology to do this exists so I asked Dr. Helen Sanders at Sage Electrochromics to share her insight into how window technology is evolving to make our homes more energy efficient.
… An Interview with Dr. Helen Sanders, VP at SAGE Electrochromics
How Windows Have Evolved
Windows began as nothing more than openings in a building's facade. Then fixed panes of glass were added and the earliest ones we recognize are the wonderful stained glass windows in European churches. Fresh air was also important so it wasn't long before window sashes were invented to allow windows to be opened and closed. In 1709, we find what might be the first window standards when London documented that windows must be recessed into their opening by at least 4 inches, to prevent the spread of fires.
We recognize today's focus on energy efficiency and windows fall under the fenestration standards set by the National Fenestration Rating Council (NFRC). Over the years, windows have become more energy efficient through the use of multiple window panes, window tinting and coating and gas filling between panes to gain improvements over air's insulating value.
Today's building energy codes require dual-pane windows that meet certain energy standards related to reducing heat loss and solar heat gain. Improvements to window design for energy efficiency go beyond multiple window panes. There's window tinting, low-E (low-emittance) coatings and/or gas fill (Argon or Krypton) to make windows more energy efficiency.
Helen explained the difference between window tinting and today's low-E window coatings. “Tinted glass has color added to the glass while coatings are applied to the surface of the glass. Most coatings appear colorless although some may have color.” Helen explained the two problems that these solutions address:
- Minimizing heat loss from heated, indoor space or heat infiltration when it's warmer outside than your air conditioned space indoors.
- Reducing solar (sun) heat gain which affects your home's indoor comfort, a problem that is more critical in warm, southern states.
Integrating Technology and Glass
My discussion with Helen focused more on the operational ease of using SageGlass products so if you want to learn more about the underlying technology, you should watch Engineering TV's interview with founder and CEO, John Van Dine.
Helen explained that picking the right windows is a balancing act between your home's needs in the winter versus warm, summer weather requirements. She also explained that the window industry is at a crossroad, where improvements to existing “static” technology is not able to achieve significantly better results.
“SageGlass products are dynamic” according to Helen. These smart windows change to meet different needs like a programmable thermostat.” Homeowners have flexibility in determining how to adjustm the windows to control heat flow. The number of ways you can program your system was impressive:
- Time-of-day clock like programmable thermostats use.
- Solar clock or light sensors.
- Temperature sensors so windows contribute to achieving your heating/cooling needs.
- Occupancy sensors so your home is more comfortable when someone is there, and more energy efficient when noone is home.
Dynamic Windows in Our Homes
New technologies get started in commercial construction and quickly migrate to high-end homes. Helen shared some of the fascinating ways SageGlass residential products are being used today.
- Homes with great views that homeowners want to preserve when it's bitter cold (ski houses around Denver) or intensely hot (Palm Springs) outside.
- Builders, interior decorators and smart homeowners who want to protect fabrics and artwork from fading due to intense solar sun rays.
- A greenhouse in Minnesota where the homeowners wanted triple pane windows with maximum thermal insulation, used SageGlass products.
- Sunrooms become comfortable for more months when the windows maximize heat gain during sunny days and reduce heat loss as the sun sets.
Helen Sanders, VP at Minnesota based SAGE Electrochromics, has 15 years’ experience in the glass industry including 10+ years experience in dynamic glass technology. She works with US and overseas clients to identify and develop new uses for SAGE's glass products, and leads SAGE’s technical services organization.
Active in industry organizations helping to defining standards, Helen chairs the GANA Energy Committee, ASTM’s Chromogenic Glazings task group and shared the SAGE story with the US Senate in 2011 (click to view video). She has a M.A. in Natural Sciences (Chemistry) and Ph.D. in Surface Science from the University of Cambridge, England.