Is Triple-Glazing Worth It?
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Triple-glazed windows are the subject of increased discussion in the industry, as window manufacturers are constantly looking to innovate and improve technology for maximum energy efficiency. If two of something are good, then aren't three even better?
Well, let’s look at that premise as it relates to windows and help you evaluate if triple-glazing is worth it for you.
How Do They Work
Triple-glazed windows feature three panes of glass equally spaced within a frame instead of two, creating two air cavities instead of one. As with double-glazed windows, the thicknesses of the sheets of glass can vary, as can the type of inert gas used in the chambers. Special coatings for different purposes can also be applied to all three glass surfaces used in a triple-glazed window.
Another key point of difference between triple- and double-glazed windows is their respective U ratings (measures of heat loss), where lower numbers indicate less heat loss. This is where significant gains can be seen with the triple construction, with their favorably lower measures:
|Old-fashioned double-glazed windows||3.0 W/m2K|
|Modern double-glazed windows||1.3-1.5 W/m2K|
|Klar double-glazed windows||1.3 W/m2K|
|Triple-glazed windows, including Klar||0.8 W/m2K|
Pros of Triple-Glazing
Besides their more efficient heat retention, there are a number of benefits when it comes to triple-glazed windows. These include greater energy efficiency, reduced condensation, a more comfortable living environment as well as enhanced home security. Let’s walk through a brief description of each of these plusses.
Greater Energy Efficiency
With this improved measure of thermal insulation, it is no surprise that one of the biggest benefits of triple-glazed windows is improved energy efficiency.
The ability of the three panes of glass to retain more heat means the difference between the interior surface of your window would be 18 degrees with triple-would glazing and 16 degrees with double when your room is heated to 21 degrees in this example.
With this warmer interior glass surface, the risk for condensation is reduced as the heat is kept inside instead of reacting with the cold air outside to form dew droplets.
More Comfortable Living Environment
The improved thermal insulation of triple-glazing quite simply makes for a more consistent internal temperature in your home with fewer cold spots and a more comfortable living environment.
Enhanced Home Security
In the case of home security, three panes of glass are indeed better than two, presenting an additional layer through which an intruder must pass. The added sheet of glass will likely serve as an even stronger deterrent to prospective burglars.
Cons of Triple Glazing
When considering whether to go with triple-glazed windows, it is a good idea to weigh the plusses against the minuses. Let’s take a closer look at the disadvantages, which include higher cost, heavier units, noise pollution, and less solar gain.
With the additional materials required to construct triple-glazed windows, one can expect the overall cost to be higher than double-glazing, with estimates ranging from 10-20% more. If triple-glazing isn’t in your budget, be sure to read our guide to double-glazed windows here, as well as our overview of various styles of double-glazed windows here.
With the extra layer of glass, as well as bulked-up framing necessary to support it, triple-glazed windows end up being quite a bit heavier than double-glazed versions. This should be taken into account so that the walls where they are to be installed offer adequate support.
Contrary to what one might expect, triple-glazing does not necessarily reduce the amount of noise pollution entering your home compared to double-glazing. The middle pane can contribute to increased vibration of sound waves and greater sound transference. When it comes to Klar’s windows, the difference is a reduction of about 1 dB between the two types.
Less Solar Gain
The three panes of glass also create an additional layer for solar rays to pass through, and they can minimise the amount of solar gain inside your home. However, using low-emissivity glass can help counter this by reflecting more heat back into the room.
Primed for Triple-Glazing
When evaluating whether triple-glazing is worth it, it is helpful to consider the specific window situation, as the investment will be more advisable in some cases.
Triple-glazing has been the most popular in countries with more extreme winter temperatures, such as Norway, Sweden, Germany and Austria. This is because the desire for superior energy efficiency in these areas is more marked, but anyone wishing to improve this quality in their home can benefit from triple-glazing.
Direction of Windows
Given the higher price tag of triple-glazing, it makes sense to select this option only for those windows in a home that are subject to consistently colder conditions, such as those that are north-facing.
Alternatively, there may be south- or west-facing windows in a home prone to the ‘greenhouse effect’ from excessive solar gain. Here too, triple-glazing can help ward off this extra heat gain.
To reap the biggest rewards from triple-glazing, it makes most sense to install them when constructing a complete high-performance structural shell, such as a new building. In this case, optimal wall and roof insulation can also be ensured, so none of the benefits of triple-glazing will be compromised.
The best example of this is in the construction of a Passivhaus, a home that adheres to a set of ultra-low energy criteria. Here triple-glazed windows with a U rating not to exceed 0.8 W/m2K are a requirement to ensure the minimal carbon footprint of the building.
What are the disadvantages of triple-glazing?
The disadvantages of triple-glazing are the increased cost, heavier product, weakened soundproofing and minimised solar gain. However, some of these can be counteracted with different glass types or coatings.
Is it worth putting in triple-glazed windows?
This is a topic of much debate, as the cost of triple-glazed windows is generally estimated at 10-20% more than double-glazed. However, the bump in energy efficiency is approximately 20-30%, and the more windows being installed, the greater the eventual benefit.
How much difference does triple-glazing make?
Triple-glazing can increase a home’s energy efficiency anywhere from 20-30% over double-glazing based on U ratings, so can make a significant difference in a home where the roof and wall insulation are also at a premium.