Triple vs. Double Pane Windows-The Pros and Cons of Double and Triple Glazed Fiberglass Windows

Double Pane Windows vs Triple Pane Windows

If you're deciding what type of glazing you want for your windows, it's more than just looking at the fact that double glazing has two panes of glass, and triple glazing has three. All factors must be looked into in order to understand the true difference between the two glazing options. Here you will find all the answers you need for understanding the differences between double pane windows and triple pane windows including the difference in cost, energy efficiency, durability and more.


Double Pane Windows

double vs triple pane windows

Double glazing windows consist of two panes of glass with a spacer that separate them. Fibertec’s standard for all windows are double glazed windows. It is required as a standard for all residential applications in Canada due to the harsher climate during the winter. Double pane windows can reduce up to 50% in heat loss, keeping your energy bills at a lower rate and in combination with a fiberglass frame, the overall energy efficiency of your fiberglass windows increase. The main benefit of double pane windows is the cost factor. The cost difference between double pane and triple pane fiberglass windows may vary. At Fibertec, the difference between the dual vs triple pane is approximately 15% while most companies reach about a 40% cost difference.

Frame Material- When looking for an energy efficient window, the frame material plays a big role in determining the quality of the window. Fiberglass frames are always the best choice. With a double pane window, Fibertec’s fiberglass frames are designed in such a way that the closed back frame can support a double glazed window without warping. Double glazed fiberglass windows may cost more up front, however over time you will be saving money.

Spacer Used- With double glazed fiberglass windows, one spacer is used to separate the panes of glass. The space left between the two panes must be correct in order to achieve proper air flow between the panes of glass. Exceeding or not achieving the right space between a double glazed window can have a great effect on the energy efficiency of the window.

Gas Fills- Double pane fiberglass windows can have a gas fill between the panes of glass for added thermal efficiency. Gases such as argon gas and krypton gas can be used as an insulator. Argon gas is often seen as a more popular choice because it is also significantly lower in price than krypton gas and is, in most cases, a more suitable gas to use for insulating fiberglass windows.

Glass- Dual glass panes perform much better than one single pane of glass, not only because of the space between the glass. The glass itself can act as an insulator as well. By using Low-E coating on the glass, infrared light is kept out while allowing visible light to enter your home. Heat mirror film is also used in combination with double glazing fiberglass windows for added insulation.

See our heat mirror windows section for more information.


Triple Pane Windows

double vs triple pane windows

Triple pane windows are an exclusive step up from double glazed windows. With three panes of glass and two spacers instead of one, triple pane windows become much heavier than double pane windows, however if fiberglass is used for frame material, it is able to withstand the weight of a triple glazed window. Despite the weight of a triple pane window, there will be no effect on the everyday use of your windows. The reason why people are much more attracted to triple pane windows is because there is a great difference in performance between a double and triple pane window. When comparing factors such as the SHGC, or U-values, there is an approximate improvement of 20-30% in a triple pane window’s energy ratings. In most cases, companies will upcharge triple glazed windows due to the fact that other companies use a double pane frame and try to put a heavier triple pane unit inside the same frame design and try dissuade customers from using triple pane units by increasing the pricing. At Fibertec, we are able to offer a fair price difference because our closed back frame was designed to easily hold a triple pane unit, and therefore we can provide a trustworthy fiberglass window, both as a triple pane or double pane.

Frame Material- As mentioned before, triple glazed windows are much heavier than double glazed windows and need a strong frame material that can be durable enough to last. Due to the properties of fiberglass, fiberglass frames are able to withstand heavy loads without twisting, warping or sagging overtime.

Spacer Used- Triple pane windows have two spacers that separate the panes of glass in a triple pane fiberglass window. Fibertec uses a spacer called the Premium Super Spacer rather than a warm edge spacer that is commonly used. The premium super spacer is made from a superior quality silicone resistant to UV light oxidation and offers great argon gas retention for higher energy efficiency. Gas Fills- The same gas fills used in double pane windows are used in the same way for triple pane fiberglass windows. The only difference is that triple pane fiberglass windows have gas injected into both air fill spaces between the panes of glass, significantly increasing the energy efficiency of a triple glazed fiberglass window.

Glass Used-Triple glazed fiberglass windows have three panes of glass. Two of three layers of a soft/hard coat low-emissivity (Low-E) film can be added on the non-exposed surfaces of the glass (one per chamber). By having three layers of glass, your windows are able to reduce outdoor noise transmitting through the windows.


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