A triple glazed window is one that contains either three layers of glass or two layers with a low-emissivity, or Low-E, film suspended between them. Triple glazed windows, which are high insulation performance, especially in colder climates, were first introduced in Sweden many years ago. Today, they are often found on new construction projects across the U.S. and Canada and are an ideal option for homeowners retrofitting older homes in colder climates.
Though a bit more expensive than other windows on the market, triple Glazed Windows are being used more and more frequently now as building codes adopt the Department of Energy's push toward R-5 windows, or hurricane-resistant windows. Triple glazed windows are beyond ASHRAE 189.1 and IGCC standards, although they are now required after the adoption of the 2012 IECC standard. Now and following latest code regulations, triple glazed windows are required in zones 7-8. The Department of Energy is also looking forward to expanding the use of triple glazed windows with its Windows Volume Purchase Program.
The most common types of triple glazed windows are:
- Triple glazed using a traditional spacer in each glazing gap.
- Triple glazed, glass in the center, with an interior U-type channel that seals between the inboard and outboard lites.
- Triple glazed windows with a suspended attached film, that will be heated allowing it to shrink and tighten to visible clarity.
Benefits of Triple Glazed Windows
These windows, when properly installed, have an extensive array of benefits. More rigid and durable than traditional windows, triple glazed windows have an outstanding insulation performance, especially in areas with extreme weather. They also are resistant to condensation and reduce sound transmission.
Their three layers of glass also provide increased security –– the thicker area is harder for vandals to break. Additionally, they offer great energy savings when compared to regular and double glazed windows.
Installing triple glazed windows is equivalent to upgrading your walls and ceilings from R-20 to R-40 (in certain circumstances), and they can decrease relative heat loss, which increases thermal comfort inside.
To cut costs, a combination of double glazed windows and triple glazed windows can be used with the building orientation. Consider insulated hollow frames when installing your windows, as they can increase their performance, which can save you money in the long-run.
Cons of Triple Glazed Windows
Like any other building material, these windows can have some issues as well. Due to the weight of containing three individual panes of glass, the windows can sometimes pose a problem with weaker sash materials, and if an existing structure has little or no wall insulation, triple glazed windows are discouraged.
The weight can also ad labor cost to your installation budget, and their casements have width limitations and sometimes are restricted when they are opened, which will need to be considered prior to installation. Additionally, Some builders have reported that because of its thickness, condensation might build up in the outside portion of the window
Financially, triple pane windows are more expensive – costing 25 to 30 percent more than double-pane windows. In extremely cold climates, the cost is worth the investment, but in milder climates, that may not be the case.
What to Look for When Buying a Triple Glazed Window
If you still want to go with a triple glazed window for your home, then you will need to review the following areas:
- Does it have argon gas in between panels?
- Does it contain low-E Glass?
- Verify the material of the center panel
- How deep is the frame?
- Are there spacer bars in between panels?
- Is a warranty offered by the manufacturer?