November 2015
Floor to ceiling windows may prove to offer a solution to rising energy costs. Or, 5-20 years into the future, these window walls may provide cold, drafty condo suites that owners are unable to afford to heat or cool.
The many condo buildings with floor to ceiling windows have been talked about because of the challenges they present. Glass has a low insulating value comparable to a few sheets of cardboard. It is transparent to the sun. This means lots of air conditioning in the summer to maintain a comfortable environment. It also means cold condo suites during the winter. A large amount of energy is needed to offset loss of heat and cool air through windows as well as the amount of heat generated by an afternoon sun coming through west facing windows.
Ontario has changed the building code allowing up to 40% of a wall to be covered with glass. This does nothing to address condo walls with more than 40% glass that predate this change.
Technology could still turn existing floor to ceiling windows into a solution for creating a building that produces as much energy as it consumes – described as a “Zero Energy” home.
Today’s windows serve two purposes. They allow the viewing of outside from indoor. They also serve to insulate the indoor from outside.
Photovoltaic double glazing is a technology that converts some of the sunlight to electricity. It is a thin coating over windows. Whatever sunlight that is not converted passes through the glass. This makes the technology potentially suitable for windows in high-rise buildings.
While not yet in use in condo buildings, this technology holds out the promise of turning high-rise condo buildings into “Zero Energy” homes.
