Last week we covered double glazed windows. We talked about the improved energy efficiency that comes as a result of the extra layer of glass used to construct the double hung window. By filling the sealed space between the panes with low heat transfer gas, the energy efficiency of the already improved window design is made even more efficient. This is one of the more significant developments in window technology for the advancement of window energy efficiency. With that under our belt, we’re going to move on to our next double glossary term. This week we are going to look at double-hung windows.

Double-hung windows are significant because they consist of two pieces, or sashes, within a single rectangular frame. In this particular kind of window, both the upper and lower halves of the window are able to slide up and down. A counterbalance is used to balance the two separate pieces of the window and ensure a smoothly sliding window. Single hung windows lack the ability to slide both the upper and lower units of the window. Double-hung windows answered the call for more window flexibility. These windows not only answered the call, but also opened a completely new world of possibly when it comes to the way a window opens and closes. By coupling the innovations of the single hung window with the almighty “double,” the flexibility of the old favorite was multiplied. As we move forward, were going to round out our exploration of double with our next glossary term, double-strength glass. As we dive into this next term, we are going to take a good look at the impact this, and other developments have had on the way we heat and cool our homes. Because energy efficiency is really the bottom line in window manufacturing, this is going to be an important point to look closely at.