How Windows Affect the Heat in Your Home

Drafty house? It could be your windows’ fault. The ability of your home’s heating system to keep you warm depends on a variety of factors, and your windows are one of the most important. Here’s what to know about how your windows to the world affect your heat.Placement is Key
Where your windows are installed can make a huge difference in the energy efficiency of your home. Windows on the east or west side of your house can lose up to twice as much treated air as those on the north or south. The best placement for windows allows overhangs like roofs to shade the windows in the summer and provide much-needed light to enter during the winter. And remember, more windows isn’t always better. Windows are always less energy efficient than walls, and the ideal ratio is about 12-15% of the total square footage of the home in windows!
The Kind of Windows Matter
The US Department of Energy estimates that around $35 billion in energy costs is lost annually through energy-inefficient windows. Poor quality, energy-inefficient windows can create the feeling of drafts. When warm air from inside your home cools hits the uninsulated pane of glass it cools quickly, then falls immediately. This creates a cycle of moving air which makes a home feel “windy”. Windows’ energy efficiency is rated through something called a “U-rating.” The lower the U-rating of a window, the better it is at keeping your home’s warm air warm. Conversely, R-values are also sometimes used to describe windows; the lower a window’s R-value, the worse it is at insulating your home.
In general, windows are most energy-efficient in this order:
Double pane, clear glass, low -e coating/film, wood or vinyl frame
Double pane, clear glass, wood or vinyl frame
Single pane, low -e coating/film, aluminum frame
Single pane, clear glass, aluminum frame
What to Do About Inefficient Windows
There are a number of things you can do to improve the energy efficiency of your windows short of replacing them all with newer ENERGYSTAR versions. Simple weather stripping around your windows can really help the movement of cold air indoors. Also available are window films, installed by professionals, that effectively work to improve the R-value of the windows without replacement. Of course, before spending money to upgrade your windows, check with a professional HVAC technician to ensure your heat is working properly in the first place.
An MTB technician can help you determine whether it’s your windows or your heating system that’s causing you trouble this winter. Give us a call today to schedule an appointment at your home.