UPDATED on May 5, 2016
Everybody has an opinion on windows, and there’s a lot to talk about. Which frame material do you prefer: wood or fiberglass? Do you like double-hungs, sliders, or casements? Who provides better warranty service, Marvin or Pella?
Window selection is a complicated topic, so I’ll approach the issue in small bites. In this article I’ll focus on glazing.
Why windows matter
Windows are crucial to a home’s thermal performance and the comfort of occupants. In a cold climate, the wrong windows will act like holes in a home’s thermal envelope, leaking tremendous amounts of heat. In contrast, the best performing windows can actually collect more heat than they lose during the winter months, turning your walls’ weakest link into an asset.
In a hot climate, windows with the wrong type of glazing are often the leading cause of summer overheating — they’re probably the main reason that your air conditioner struggles to keep your home cool on summer afternoons. That’s why the right type of glazing can transform an unlivable room into a pleasant oasis.
If you are building a new home, the cost to upgrade from run-of-the-mill windows to high-performance windows is relatively small, and the incremental cost can easily be justified by future energy savings. Upgrading to better windows will never be cheaper than during new construction.
If your existing home has bad windows, however, the cost to replace every window in your home with new high-performance windows is often prohibitive. After all, the cost to replace an existing window will always be significantly more than the incremental cost to upgrade to better windows when the house is being built.
Old-fashioned single-glazed windows have been relegated to garages and barns. These days, the vast majority of new…