Double glazed windows cut down on noise while providing thermal insulation. Popular in new home construction, double glazed windows can also replace existing single pane windows. While some installations and replacements are suitable for do-it-yourselfers, there are some things to take into consideration before deciding on double glazed windows. 

What is Double Glazing?

A double glazed window is a frame with two panes of glass that are sealed with an interstitial space filled with an inert gas to prevent fogging. This not only improves the window’s insulating properties, but also significantly improves acoustic insulation. Another type of double glazed installation comes from adding PVC windows directly over existing windows. 

Replacing or Retrofitting

Double glazed windows will cost more to install than standard single glaze windows. While the savings in heating and cooling costs may be considerable in the long term, you’ll need to decide whether it’s worth the extra cost of installation. If the entire frame is rotted out, then a self-contained double glazed window may be a feasible option. However, if the frames are in good condition, then a PVC retrofit may be the way to go. 

Noise Reduction

As a general rule, the greater the gap between the panes, the better the insulation against noise. A standard double glaze window has a 6 mm gap, while a PVC retrofit (with its discreet framing system and external fasteners) may have up to  a 100 mm gap and provide even greater noise reduction. Studies have shown a 75 percent decrease in noise after PVC window installation. 

Extreme noise reduction can be accomplished by installing double glazed windows coupled with an exterior PVC window.