Windows
Windows are an aesthetically pleasing part of the home, but they also have an ugly side when the heating bill shows up. Unfortunately, windows account for 10% to 25% of the bill(US Department od Energy). One way to save energy and money is to replace old single-pane windows with double-pane Low-e windows.
Example:
$126–$465 a year when replacing single-pane windows
$27–$111 a year over double-pane, clear glass replacement windows
Some other ways to save is by windows that are replaced seasonally between cold climate and warm climate temperature.
Cold climate left:keeps heat in.
Warm climate right:keeps heat out.
http://www1.eere.energy.gov/consumer/tips/windows.html