Week 26 - April 28, 2011 Today: The energy model for the house / Part III: Windows by Greg McMillan of TheGreenHub.ca

We have to give home designer Corwyn Perrin a lot of credit. As much as possible, in his redesign for the house at 87 Alexander Drive, the subject of This Really Old House Goes Green project, he tried to reuse existing windows wherever possible.

But after a subsequent meeting with technical advisor Dara Bowser, where more discussion about energy-efficiency windows took place, the TROHGG team decided, as a group, to revisit the final decisions about windows further along in the project.

And for good reason, as it turns out. Both experts agreed that a window specialist, when that person joins the TROHGG team, should be the one to make the ultimate final call.

"With energy-efficient windows, who and how they are installed makes a tremendous difference," said Perrin, of MC Developments. "They would look at the type of window being purchased, the type and material of the frame and how the glass pane is manufactured."

Bowser said, with replacement windows, installation quality makes a huge difference.
"A good window poorly installed may leak air or water and may not operate properly," said Bowser, of Bowser Technical. The Siding and Window Dealers Association of Canada (SAWDAC) operates a 'window-wise' program (www.windowwise.com) to help consumers in identifying quality assured windows and installers."

When all is said and done, however, Bowser stressed that the main objective in this project is to have all the windows at, or close to, an EnergyStar Zone D model, which has an internationally-designated rating based on energy-conservation and climate zone.

"Many of the newer replacement windows currently in the house are 'close to' to the specification, and so they should be retained and reused where possible," Bowser said. "If not reusable, they can go to the Habitat for Humanity Brant ReStore to find a new home.

"The older replacement windows with non-insulating spacers will be replaced with Zone D windows. The existing basement windows will all be replaced for energy reasons."

Perrin added that windows not meeting Ontario Building Code (OBC) requirements would be replaced.
"This would all be relevant to the installers and suppliers that join the TROHGG team and how they would want to showcase their talents and products."

Both experts cautioned average homeowners to do their research before buying any type of window.
"They need to understand the differences available rather than just taking someone's advice," Perrin said.

In a green reno, Bowser said that there always has to be a balance between materials' conservation and energy efficiency. "In the case of TROHGG, we have to set the bar fairly high, so we will only be keeping the windows that are 'almost as good as' a new, high-efficiency window."

He stressed that an Energy Star rating is the first criteria. "Windows are rated according to zones with A being the warmest and D being the coldest," he explained. "The colder zone windows are the best energy performers."

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Photo illustration by Tae McIntosh of Tae Photography