To be an informed window shopper you need to know that glass can make or break the efficiency of a window. Before you invest in new windows for your home, consider the type of glass that will work best for your environment. This will ensure that you are getting the most out of your investment.
Glass coatings aside, you have three options when it comes to glass panes in your windows: single, double, or triple panes.
What’s the difference?
Simply put, triple pane windows use three panes of glass for a window. There’s an interior pane, an exterior pane, and a pane in between those two. Double pane windows use two panes of glass. With either double or triple pane glass, gas can be applied between the panes instead of air. Odorless, non-toxic gas (Argon or Krypton) is often used in triple and double pane windows to increase energy efficiency. Single pane windows use just one pane of glass separating the indoors from the outdoors. Many manufacturers have stopped making single pane windows because it is not compliant with current energy codes. Image from Glass and Glazing Federation (GGF). Window glass is often called glazing.
Consumers looking for the best window value are increasingly looking towards double pane and triple pane windows. The first consideration for homeowners should be double pane glass because they are less expensive than triple pane glass and can often meet the same needs as triple pane without the additional expense. That may not always be the case depending on the climate where you live so let's dive into a few things you need to know about triple pane windows for now and we'll cover more on double pane windows in another article.
In this article we’ll look at 3 key factors of triple pane windows homeowners should be aware of:
- Energy performance
- Noise cancellation
How much do triple pane windows cost?
Triple pane windows come at a high cost with questionable ROI.
With extra glass and mechanisms to support the frame, you’ll find that triple pane windows are on the pricier side.
We’ll use our Brennan Traditions windows to give you an idea of pricing; these costs don’t include installation or other fees often associated with window replacement projects:
- Brennan Traditions single-hung window in white with high-performance glass
- Double Pane glass: $545
- Triple Pane glass: $622
So for a project requiring 20 windows, triple pane windows will cost you over $1,500 more than double pane windows.
These are important numbers to keep in mind considering that Hanley Wood’s Remodeling 2018 Cost vs. Value Report showed that nationally the average ROI for a vinyl window replacement was 74.3% and the national average ROI for a wood window replacement was 69.5%. For those in the South, Dallas, for example, the average vinyl window replacement project had a 71.9% ROI and 68.2% ROI for wood window replacement projects.
Now, with a serious window investment, you’ll want to ensure a high return via performance. That leads us to our next point of review: energy (and cost) efficiency.
Are triple pane windows worth the energy efficiency savings?
Is three always greater than two? Not for all of us.
For the Northern climates, triple pane makes more sense. One of the main selling points of triple pane windows is the benefit of maximizing U-value. It's a myth that the extra layer of glass regulates home temperatures, glass, in fact, is a thermal conductor, not an insulator. The gas between the glass panes is the actual insulator. Multiple panes of glass are used to provide the ability to put denser gas into the glass package. This gas acts as a roadblock to cold air transfer in extreme sustained low temperature. Triple pane windows may offer more energy savings in Northern climates due to their high R-value, low u-value, and high SHGC.
- R-value measures a window’s ability to resist heat flow. A higher number means more resistance. In a state like Texas, R-value is less important because our winters aren't as cold or as long as those in the North (we care more about blocking the heat).
- U-factor measures a window’s insulation ability to block the transfer of cold air on a scale of 0.20 to 1.20. A lower U-factor is better because it means higher insulation capabilities.
- The Solar Heat Gain Coefficient (SHGC) measures a window’s ability to block heat producing solar rays on a scale of 0 to 1 (a lower SHGC number is better).
In North Texas, the lack of severe winters means fewer opportunities for triple pane windows to really show you energy cost-savings. According to ENERGY STAR, windows in our climate are most efficient with a higher U-factor around 0.30 and a lower SHGC around 0.25. Opposite of what’s offered with triple pane windows.
In short, triple pane windows are an expensive and unnecessary option for those of us in Texas but could certainly be beneficial to those living in states where extreme winters are common.
ENERGY STAR climate zones
ENERGY STAR performance criteria by climate zone
Do triple pane windows reduce noise?
Reducing outside noises inside is something many of us seek to do but can triple pane windows help us cancel outside noise?
The glass and gas of windows help to muffle outside noise because they provide a barrier between the inside and outside. So an extra layer of glass should help with noise reduction, right?
Well if you are opting for triple pane windows for noise reduction alone you’re about to overspend. Tests on noise reduction performance between double and triple pane windows found little difference between the two. As a matter of fact, smaller airspaces have been shown to cause a reverberation in sound waves. Triple pane windows have less space between the glass than double pane windows because more panes are being fit into an already narrow space. So while there is additional insulation for thermal performance there is no added noise reducing benefit with a third pane of glass.
Want noise reducing windows? Double pane glass is your best and most cost-efficient choice.
So, there you have it. Triple pane windows are an option for everyone but we don't recommend them for homeowners warm regions and we don't recommend them for homeowners in our state of Texas. Although they are an option for us in the South they are expensive, don't provide a significant difference in energy value, and don’t do much in the way of noise reduction.
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