Triple Pane vs. Double Pane Windows
What is the difference between Triple Pane and Double Pane Windows?
Triple pane windows have an additional glass pane within the window frame, increasing the unit’s thermal efficiency, soundproofing, and overall performance. Triple pane windows and doors have become a staple in Europe, with manufacturers, such as Internorm, pioneering this technology as early as the 1970s.
On the other hand, North American window manufacturers have yet to make the transition toward high-performing and energy-efficient alternatives, with double pane windows still being the prevalent choice today. Not to mention, there is a very noticeable difference between the construction of triple pane North American and triple pane European windows. We will highlight the most important properties of a window and how to distinguish differences in quality.
Key Performance Characteristics – Not all Triple Pane Windows are made equal.
For one, the glass thickness and construction depth of North American windows are significantly lower, in turn, making them much more susceptible to heat loss and condensation. The opening mechanisms of North American windows (casement, awning, sliding, etc.) cannot support the weight of large glass surface areas and are, therefore, limited to certain dimensions and glass specifications. As a result, the overall performance is severely compromised.
On the contrary, the tilt-and-turn functionality of European windows can accommodate very large dimensions, glass weights up to 300 lbs, and a variety of design options, thanks to a robust and wider window frame. Let’s compare the two:
North American Windows
6 – 8 mm
European: 6 – 8 mm
3 – 4 mm
North American: 3 – 4 mm
Total Glazing Width
(Glass panes and spacers)
48 – 54 mm
European: 48 – 54 mm
North American: 24 – 26 mm
Total Sash Construction Depth
71 – 93 mm
European: 71 – 93 mm
70 – 76 mm
North American: 70 – 76 mm
Think of your home’s windows as being just as resilient as the exterior walls. A window should be able to keep the home’s interior at a stable temperature and should mimic the same qualities of the surrounding walls in terms of airtightness, weatherproofing, insulation, low-conductivity, etc. Windows offer much more value to your home than merely a means of natural light or an additional design feature. They seal the interior from the elements and play an important role in the quality of your home, including maintaining healthy humidity levels, reducing allergens and dust, and improving your overall comfort.
Thermal Imaging: Before & After Triple Pane Window Installation
BEFORE – Double Pane Casement Windows
Poor performance of the window system created a weak spot in the building envelope, resulting in heat loss and high energy costs.
AFTER – Internorm® European Triple Pane Windows
Significant improvement in the home’s energy efficiency, as the high performing window system maintains stable temperatures and reinforces the exterior walls.
How to Compare Performance: U Factor & Solar Heat Gain Coefficient (SHGC)
The U Factor or U Value is a measure of the window’s overall level of conductivity, including both the frame and the glass. It represents the difference between the exterior and interior temperature of the window. The lower the U value, the greater the performance and insulation properties of the whole unit. For example, on a -20°C winter day, the interior glass temperature of a high-performance triple glazed window will remain steady at 20°C, minimizing unwanted heat loss and reducing your energy expenses. The U Value of European products is expressed in Watts, whereas in North America it is expressed in BTUs.
To convert the U Factor from BTUs to Watts, simply multiply the value in BTUs by 5.678. For example, if a window has a U Factor of 0.21 Btu/h·ft2·F, then 0.21 x 5.678 = 1.19 (W/m2K).
U Factor in W/m2K (Europe)
U Factor in Btu/h·ft2·F (North America)
U Factor in W/m2K (Europe)
European triple glazed windows typically have a U Factor between 0.90 to 0.50 (W/m2K), which equates to 0.16 to 0.09 (Btu/h·ft2·F).
U Factor in Btu/h·ft2·F
North American triple glazed windows typically have a U Factor between 1.14 to 1.82 (W/m2K), which is equal to 0.20 to 0.32 (Btu/h·ft2·F).
Solar Heat Gain Coefficient
Glazing and sun-orientation are two key factors that allow a home to reap the benefits of natural heat sources, which significantly reduce both energy consumption and heat loss.
The Solar Heat Gain Coefficient (SHGC) indicates the amount of heat transmitted through the glass when exposed to direct sunlight. It is expressed as a value between 0 and 1. The lower the SHGC, the lower the amount of heat transferred into the home.
Increasing or reducing the SHGC for rooms that lack or allow too much natural sunlight into the home can have a significant impact on energy efficiency. During winter, an increased SHGC allows more heat to be transmitted into the home, particularly in rooms that are oriented away from the sun for most of the day.
In the summer, the SHGC of windows that have more exposure to sunlight should be lower, so as to avoid overheating. These values are usually tailored to each home accordingly. It is a cost-effective and convenient means of stabilizing indoor temperatures.
Here’s how you can improve the quality of your home with triple glazed windows:
1. Significantly improve energy efficiency
2. Experience comfort in your home all year round
3. Better soundproofing
4. A healthier home
*It is often suggested by manufacturers to lower the level of relative humidity in your home down to 20%, especially during the winter months, in order to avoid condensation. However, this should not be encouraged, as it increases the number of bacteria and other unhealthy particles in the air.
How much do triple pane windows cost?
There is the common misconception that triple pane windows are not affordable. In fact, there is only a 10 to 15% difference in price compared to double glazed windows. This increase in price, however, doubles the performance of the window and significantly increases its durability. You are not only saving money on monthly energy bills, but making a future-proof investment that requires little to no maintenance, improves the air quality and comfort in your home, and has a lifespan of 40 to 50 years, compared to the average 10 to 15 years of double glazed windows. It is an investment that will stand the test of time and will perform under the conditions of our harsh Canadian winters and humid summers. It may very well be the first and last time you install new windows and doors in your home.
Important considerations before making your window purchase:
Thermally Broken Frame
Is the window frame thermally broken?
A thermal break is a portion of the frame that is used to create a barrier between a non-conductive and conductive material. For example, UPVC and Aluminum. This is a key indicator of the insulation properties and overall energy efficiency of the window unit.
Glass Thickness & Spacers
Which material is used to separate the glass panes?
The performance of the glass heavily relies upon both its thickness and the material used to separate each pane. A non-conductive material, such as ISO, reinforces the window’s insulation, removes moisture, and prevents condensation.
Number of gaskets
How many gaskets are in the window frame?
The number of gaskets within the window frame has a significant impact on sound reduction, water drainage, and air leakage. 3 continuous gaskets protect the hardware from the elements and reduce maintenance. This is a standard feature across the Internorm® product line.
Selection of Materials
What is the best choice for your home?
Materials, such as UPVC, Aluminum, Wood, or a combination of two, are better suited for certain climates. Homes located on waterfronts or in very windy locations may require additional protection. Speak to a product specialist about protective coating options.
Discover our wide selection of Triple Pane European Windows, Aluminum Windows, Lift-and-Slide Doors, and more.
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