Recently, Home Energy Publisher Tom White participated in an interview with "Replacement Windows for Dummies," the popular book series known for approachable information on nearly every topic. They discussed what's new in the world of windows, tips on hiring qualified window installers, and much more. Below is a snippet of their conversation.
RWFD: What are some of the most significant new developments in energy efficient windows that benefit homeowners?
TW: There are some new technologies that DIYers can take advantage of in terms of different types of windows. In terms of the glazing or the glass unit themselves, there are recent developments in high performance windows and the core of the modern high performance window is the insulating glass unit. That’s the sealed assembly of two or more coated layers of glass and often they’re constructed with inert gas in between the panes that provides insulation. Sometimes they have films applied or even four layers of glass depending on the insulation value that you’re going for.
There are also new coatings that are being applied to lower the emittance of the radiation coming through the window and you can choose spectrally-select coatings which are often referred to as low E coatings. So if you want to have light coming in on the west side of your house but you are concerned about increasing your air conditioning bill because it might get too hot, there are types of spectrally-selective window coatings that will let the visible light in but will block the infra-red light spectrum, which is what we perceive as heat.
Additionally, there are new types of window frames that are low conducting. Typically, aluminum framed windows have a very high conductance but vinyl and composite frames have lower conductance and therefore higher insulating value. So there have been improvements in the framing as well as in the insulating glass unit and the types of glazings and coatings applied to the glass itself.
RWFD: What are some simple things a homeowner can do with the windows in their homes--short of replacing them--to save energy and money?
TW: A lot of older homes have windows that just need a little bit of tightening up--perhaps the wood has shrunk over the years or the house may have settled some. So you may just need to add some bronze metal or some other type of weather stripping or air sealing in the window channels. You can also apply felt to the window ledges to keep air out.
The primary concern with older windows is that they’re a source of air infiltration so if you can keep the sides of the windows plumb that helps to seal them. If the windows are not well aligned with the frame and the putty that holds the glass in the frame is not tight, you may be getting air in from around the glass itself. Plus there are films that can be applied to windows that will lower the amount of conductance and lower the heat gain. In order to provide more insulation, you can add things like storm windows or shutters on the outside of the window and there are even window quilts which you can use to both lower the amount of air coming into the home and improve the window’s insulation value.
Read the entire interview at ReplacementWindowsForDummies.com.