Despite the claims, you most likely will not save enough money in energy to pay for the windows. Not that energy savings are minimal. It's more that replacement windows are so expensive it would take decades to earn back their cost. Still, you can save quite a bit of money with replacement windows.

Your State	If your current window is a single-paned* you will save this much:	If your current window is a double-paned** you will save this much:
Alabama	$230	$45
Alaska	$360	$45
Arizona	$325	$55
Arkansas	$210	$70
California	$110	$20
Colorado	$325	$55
Connecticut	$400	$75
Delaware	$350	$75
District of Columbia	$345	$50
Florida	$160	$90
Georgia	$345	$50
Idaho	$325	$55
Illinois	$310	$65
Indiana	$310	$65
Iowa	$280	$60
Kansas	$280	$60
Kentucky	$230	$45
Louisiana	$210	$70
Maryland	$345	$50
Maine	$400	$75
Massachusetts	$400	$75
Michigan	$310	$65
Minnesota	$280	$60
Mississippi	$230	$45
Missouri	$280	$60
Montana	$325	$55
Nebraska	$280	$60
Nevada	$325	$55
New Hampshire	$400	$75
New Jersey	$350	$75
New Mexico	$325	$55
New York	$350	$75
North Carolina	$345	$50
North Dakota	$280	$60
Ohio	$310	$65
Oklahoma	$210	$70
Oregon	$360	$45
Pennsylvania	$350	$75
Rhode Island	$400	$75
South Carolina	$345	$50
South Dakota	$280	$60
Tennessee	$230	$45
Texas	$210	$70
Utah	$325	$55
Vermont	$400	$75
Virginia	$345	$50
Washington	$360	$45
West Virginia	$345	$50
Wisconsin	$310	$65
Wyoming	$325	$55

*Based on current single-paned window with wood, vinyl, or aluminum frame, and by replacing it with a double-paned EnergyStar-rated window.

**Based on a current, non EnergyStar-rated double-paned clear-glass window with wood, vinyl, or aluminum frame, and by replacing with a double-paned EnergyStar-rated window.