Double & triple-paned windows feature two or three panes of glass respectively separated by a layer of gas. This design helps to reduce sound transmission and keeps the home more comfortable than old-fashioned single-paned windows. It is beneficial to consider how they compare with each other in terms of efficiency, sound transmission and cost.

Technical Breakdown

R-Value
The R-value of a window measures its ability to resist heat flow. A window with a higher R-value is more effective at blocking heat transfer than one with a low R-value. To keep your home warm during the winter and keep expensive heat from escaping through the window panes, look for units with the highest R-value possible. Replacing double-paned units with triple-paned windows could reduce heating costs.

Solar Heat Gain
In addition to R-value, it’s also important to understand how well a window blocks solar heat gain or it’s solar heat gain coefficient (SHGC). This SHGC ranges from 0 to 1. A low SHGC means that the window does an excellent job blocking heat-producing solar rays, while a high SHGC allows more solar heat gain into the home. In northern climates, a high SHGC may be desirable because it helps keep the home warmer. In general, triple-paned windows have a lower SHGC than double-paned units.

Cost Evaluation
Triple-paned windows cost 10 percent to 15 percent more than double-paned ones on average. The improved efficiency of triple-paned windows could cut heating bills by 2 to 3 percent a year in very cold areas but may not save buyers much in more moderate climate zones.

Sound Transmission
There are differing opinions on how much sound transmission is eliminated by triple-paned windows. The extruded frame for a triple-pane window profile is thicker than a dual pane profile. Noticeable or not, triple-paned windows will reduce sound transmission as there is physically more barriers for the sound to travel through.