Time to close the windows
Glenn MacEachern of ECO Insulating Glass [www.ecoglass.ca ] makes the case for closing the windows on energy-efficient buildings.
SABMag: There’s lots of glazing being used on buildings, but what are you seeing out there?
GM: We’re seeing new buildings with standard dual pane insulated glass [IG] units with a R-2 insulating value, a technology invented 80 years ago. Many commercial buildings are are using Low-E IG units or IG units of Low-E glass filled with argon which provide only R-3 or R-4 performance. It’s almost like leaving the windows open. To save energy, builders are turning to the latest technologies: digital addressable lighting interface lighting controls, underfloor air distribution systems, HVAC controls, smart grid technology and more. They are missing the obvious: insulate the windows where 30% of energy loss occurs.
SABMag: ECO Insulating Glass makes insulated glass [IG] units, so what is the message from your company?
GM: ECO Insulating Glass has been offering ECOGLASS/HM IG units, with R-values of R-8 to R-20, for 20 years. Builders can “tune” the glass performance based on the building’s exposure to maximize energy savings and daylighting. They also get the additional benefits of 99.5% UV protection, better condensation control, sound control values up to STC 49, and a better level of comfort that affects the quality of the work environment.
SABMag: What’s behind the high R-values ?
GM: We use Heat Mirror™ technology which was developed by Southwall Technologies back in the 1980s. In 1999, Heat Mirror™ was recognized by Popular Science Magazine as one of the Top 100 Inventions of the Millennium” so it is a well-tested technology.
SABMag: What about the extra weight of insulated IG units ?
GM: Triple-pane IG units often have an extra layer of glass which makes them 50% heavier than ECOGLASS/HM at only half the insulating value. The extra weight increases the dead load, and complicates transportation and installation. ECOGLASS/HM Quad units have two interior Low-E films that add nothing to the weight of the IG units but can deliver R-14 insulation. The weight is the same as a dual pane IG unit but the insulating value is equal to a wall.
SABMag: What about the higher up-front cost for your IG units?
GM: Yes, that can be said of most high-performance building products. But, as energy prices continue to rise, it makes dollars and sense in the long run to make the investment up front.
The Empire State Building was retrofitted with 6,500 windows with Heat Mirror™ glass that upgraded the glass from R-2 to R-8, which has reduced annual energy costs by over $400,000. The payback is estimated at three years. Our experience has been that retrofitting existing glass with high-performance IG units can pay for itself in three to five years, and save millions of dollars of energy costs over the next 25 years.
SABMag: What has been the market acceptance?
GM : Over 200 Million square feet of Heat Mirror™ high R-value IG units have been installed around the world, and it’s been well tested in Canada. The IQALUIT Hospital in Nunavut chose ECOGLASS/HM IG units with an insulating value of R-20. This configuration includes three Low-E films creating four air chambers filled with a Krypton/Xenon gas combination, giving the windows the same insulating value as the walls.
The retrofit of the Enwave Theatre at Harbourfront in Toronto saw ECOGLASS/HM IG units integrated with photovotaics and installed into 40-year old steel frames. Concordia University testing revealed an insulating value of R-5 for the IG units in the envelope, and energy is also generated through the photovotaics.
Given their production requirements and superior performance, it is to be expected that the types of products we make are more expensive. But the issue is investment value, not cost. After a short payback the rest is pure energy savings for the next 20 years. It’s time to close the windows.