Have you decided to invest in replacement double-pane and triple-pane windows? First, learn the pros and cons of double-pane and triple-pane windows. What made you finally decide to leap? Was it the incredible energy-saving benefits new windows offer? If so, you’re not alone. For a typical home, 40% of the annual energy budget goes toward heating and cooling costs, and replacing the windows in your home is a great way to keep more of that money in your pocket. Some municipalities are leaning towards requiring triple-pane windows. First, learn the pros and cons of double and triple-pane windows
The pros and cons of double-pane and triple-pane windows easily justify replacing single-pane windows. First, one must consider energy efficiency as an important factor when choosing replacement windows. How much more efficiency do triple-pane windows offer compared to double-pane windows? Do the savings in energy bills pay for themselves? This is an important question to address. But deciding between these two window types isn’t as easy as calculating the cost or thermal efficiency. We will address many of the important factors in the following passage. The illustration above shows the features that constitute the benefits of double-pane windows and triple-pane windows.
Know Why Double Pane Windows are Best
If you break down the math, double-pane windows are the best bang for the buck. Double-pane windows are a vast improvement over single-pane windows, but triple-pane windows are only an incremental improvement over double-pane windows. This is probably why it is the number one window choice in the entire country. When you upgrade your current windows to double-pane windows, you’re going to notice the difference. Since triple pane windows can cost ⅓ more than double pane windows, it makes sense to go with double pane windows unless you are in a very cold climate.
A standard double-pane window with argon gas reflects 90% of the energy and lets only 10% through. That means on a sunny day, 90% of the heat from the sun stays outside, and only 10% gets in. On a cold winter day, 90% of the heat from your furnace is going to stay inside your home, and only 10% is going to leak out. In comparison, a typical triple-pane window will reflect 97% of energy and only allow 3% to pass through.
Do you like natural light? When you have two panes of glass instead of three, you’re going to have fewer coatings for the sun to get through. That means double-pane windows allow more light into your home, an illuminating difference.
Reasons to Choose Triple Pane Windows
Those who choose triple-pane windows often do so for comfort. If you measure the temperature on the inside glass of a double-pane window and a triple-pane window on a cold winter day, the interior glass of the double-pane window is going to be cooler. For this reason, homes with triple-glazed windows are warmer and cozier. Triple-pane windows provide a more uniform temperature, often within a degree or two of the wall temperature at any given time. A building seems less drafty. This creates a high level of occupant comfort and reduces convection currents and drafts. If comfort is your top priority, triple-pane windows are the best option.
A reduction in energy bills isn’t the only reason to choose triple-pane glass. Some look for a reduction in noise. The extra pane of glass makes this window option the number one choice for keeping noise out. If you have noisy neighbors or live near a busy street, triple-pane windows can really make a difference.
If noise reduction appeals to you, there is a good chance you’re in a city. That means you’re likely to prefer triple-pane glass for the extra security as well. The glass may have the same technology used in automotive windshield design.
Getting New Windows is a Big Improvement
Both double and triple-pane windows provide an immediate benefit. Replacing single-pane windows offers benefits, regardless of the glass option chosen. Window technologies have advanced. Having windows that make a good seal is just as important as getting modern ENERGY STAR efficiency.
Triple-pane windows are an exclusive step up from double-glazed windows. Triple-pane windows weigh more than double-pane windows. However, fiberglass frames can withstand the weight of a triple-glazed window. Double-pane windows help significantly to address a condensation problem. Poorly insulated windows allow heat near them to escape, making them feel as cool as the exterior. Triple-pane windows will maintain a slightly warmer surface temperature than double-pane windows.
Double Pane Windows Pros and Cons
Double-glazed (double-pane) windows consist of two panes of glass separated by a spacer. Many building codes effectively require at least dual-pane windows to meet energy-efficiency requirements. Double-pane windows can reduce heat loss by 50% or more, keeping your energy bills lower, and, combined with a fiberglass frame, the overall energy efficiency of your fiberglass windows increases. The main benefit of double-pane windows is their cost. The cost difference between double-pane and triple-pane fiberglass windows may vary. For example, at one company, the difference between dual-pane and triple-pane windows is only approximately 15%, whereas many companies show a 40% cost difference. The cost difference can be an important factor to consider.
Window Frame Material Selection
When looking for an energy-efficient window, the frame material plays a big role in determining the window’s quality. For a double-pane window, fiberglass frames make the best choice. They generally use closed-back frames, but not all companies offer them. They 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. Aluminum may be robust, but aluminum frames conduct heat very well, which is exactly the opposite of the design goal for a thermally insulating window.
Spacers Used
PROS AND CONS: Double-glazed fiberglass windows employ only one spacer to separate the panes of glass. The space between the two panes must be correct to ensure proper airflow between the panes of glass. Exceeding or not achieving the right spacing between a double-glazed window can significantly affect its energy efficiency.
Gas Fills Between the Windows Panes
PROS AND CONS of two different gas fills: Double-pane fiberglass windows can have a gas fill between the panes of glass for added thermal efficiency. Gases such as argon (Ar) and krypton (Kr) are effective insulators. The lower cost of Argon gas makes it a more popular choice than krypton gas. Both are dry gases and, absent a leak, will not condense moisture between the panes. If you have every had dual-pane windows become cloudy, you would realize that moisture accumulation between the panes is their kryponite – haha. (Kryptonite is a fictional material.) The cost to re-pane and replace dual pane windows that condense moisture between the two panes is prohibititve and can be as much as new windows.
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PROS AND CONS: Dual glass panes perform much better than a 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 a Low-E coating on the glass, infrared light is kept out while visible light is allowed to enter your home. Double-pane windows employ both reflective films and double-glazed fiberglass for added insulation and thermal efficiency.
Triple Pane Windows-Pros and Cons
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. If fiberglass is used as the frame material, it can 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 people are more inclined to choose triple-pane windows is that there is a significant performance difference between double-pane and triple-pane windows. When comparing factors such as the solar heat gain coefficient (SHGC) [1] or non-solar heat loss, the U-values [2], there is an approximate 20-30% improvement in a triple-pane window’s energy ratings. In most cases, companies will upcharge triple-glazed windows because other companies use a double-pane frame and try to put a heavier triple-pane unit inside the same frame design. They also try to dissuade customers from using triple-pane units by raising prices.
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 its properties, fiberglass can withstand heavy loads without twisting, warping, or sagging over time.
Triple-pane windows have two spacers that separate the panes of glass. Using a spacer made from a superior-quality silicone resistant to UV light and oxidation offers excellent argon gas retention for higher energy efficiency.
Spacer Used
Double-pane windows and triple-pane fiberglass windows may utilize the same gas fill or spacers. The only difference is that triple-pane fiberglass windows have gas injected into both air-filled 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.
Low-emissivity Glass
Manufacturers apply two of the three layers of a low-emissivity (low-E) or reflective film to the non-exposed surfaces of the glass (one per chamber). With three layers of glass, your windows can reduce the transmission of outdoor noise. Glew Engineering has offered expert testimony in legal disputes over equipment used for low-E window coatings. When one sees a skyscraper where the glass looks dark, that is likely low-E glass, that is reflecting the outside solar heat and keeps the heat inside at night
It’s cool that double-pane windows will be able to withstand harsher climates. My boss wants to build a machine that drops that temperature of the surrounding area, and he wants to make sure that it can be viewed in safety. I’ll share this information with him so that he can look further into his options for getting double-pane windows for it in the future.
Best of luck with your project. Are you considering triple pane windows? Some of the new zero energy buildings are seriously contemplating that as a solution.