Published: June 2, 2021
What is a double glazed window?
Often mistaken for window films, tints and coatings, window glazing simply refers to the pane(s) of glass installed in a window frame (or wall opening).
It’s not a treatment done to the glass, it’s the glass itself.
Glazing can also reference other types of translucent material used in a window frame or wall opening, such as sheets of plexiglass/acrylic or lexan.
Since glazing refers to the glass, it makes sense that double glazed windows have two panes of glass, and triple glazed have three. Commonly used by tradesmen and manufacturers in the windows industry, the term “double glazed window” is interchangeable with “double-pane window,” the name homeowners and other consumers may be more familiar with. Similarly, triple glazed windows are more commonly called triple-pane windows.
Gotta love trade jargon, right?
Glazed vs glazing compound
Not to confuse the issue, but the compound used to seal glass to a window frame is also commonly called window glaze, glazing compound or glazing putty. It’s a mixture similar to caulking but with a different texture and elasticity to adhere the glass to the frame, and prevent water and air leaks. It’s something you’d expect to see a glass repair company (or “glazier”) use if they’re swapping out a pane of glass or replacing a sealed glass unit, which is commonly seen for glass repair in a double or triple glazed window, which are assembled and sealed as a unit to lock in the gas insulation.
Materials or methods used to secure glass to the window frame during manufacturing may be different, since glazing compound isn’t always necessary or appropriate, depending on the frame material. For example, a vinyl or fiberglass window is unlikely to need glazing compound, but a wood one might.
So how do double glazed windows—AKA double pane windows—save money?
Energy efficiency of double glazed windows is all about the space between the panes, which helps insulate the glass. Depending on the options and upgrades, it provides varying levels of energy savings.
A standard double glazed window without upgrades relies on the cushion of air between the glazing to break heat transfer, helping keep air conditioning and heat inside the home, and cool or hot air outdoors from entering. It’s the basic standard for windows, now that single glazed windows are outdated and rarely used. Most manufacturers don’t even make them, other than rudimentary utility windows intended for outdoor spaces like garages and enclosed sun rooms.
For a minimal cost, upgrading to include argon is well worth the investment, according to DunRite Windows & Doors Owner Sal Sucato. Because it’s a colorless gas that’s denser than air, it helps keep the glass on the inside of the home at room temperature. The air conditioner (or heater) doesn’t have to work as hard to keep the room cool, since heat or chill isn’t being transferred.
Argon gas also helps deaden outdoor sound, something helpful in screening out the neighbor’s barking dog and playing children.
To get the most energy efficiency possible, adding a low-e (low emission) coating upgrade is also an essential upgrade for Arizona homes. It’s an inexpensive way to allow light into a home without the heat.
So what is low-e glass? It has a silver oxide coating to reflect heat, minimizing the infrared and UV light coming through the glass while reflecting interior temperatures back inside the home.
“You can’t go wrong choosing upgrades related to low-E,” adds Sucato. “These help glass reflect heat of the sun so it doesn’t enter the home, retain heat inside the home during the winter, and block UV rays that can harm furniture, art and window coverings.”
According to Energy Star, this can save as much as 31% on annual HVAC costs if replacing single glazed, and an average of 17% when replacing old double glazed windows. Argon gas and low-e upgrades quickly pay for themselves.