Dear Ms. Green,
I just bought an older home and its energy bills seem high. I’m thinking of getting new windows to help with the bills. What can you tell me about replacement windows?
–Cold in Carrboro
Here’s what Ms. Green thinks about replacement windows: contrary to what the window replacement industry will tell you, getting replacement windows is not a very good use of your energy efficiency dollars.
But they’re leaky, you’ll say. I can literally feel the air coming from around the jams!
No doubt, Ms. Green replies. They might be leaky. But there are better, cheaper solutions than spending $400 and up per window, especially considering it will take twenty years (and probably more) to earn your money back in energy savings.
Let’s do the math.
If a replacement window costs you $400 (and yes, Ms. Green knows you can get windows cheaper than this, but she also knows you can pay much, much more than this, so she’s sticking with $400), and you have 15 windows in your house (again, kind of arbitrary), and you’re going from single pane older windows to double-pane low-e Energ yStar windows, according to energystar.gov, you can expect to save $247 per year in energy costs in the Southeast. (If you’re going from double pane to energy efficient double pane your savings is less than $70/year!)
So you spent $6000 on new windows and your projected savings is $247 per year. That means that it will take you 24 or so years to get a return on your investment. Less time if energy prices go up, of course, but still. 24 years for payback? Are you kidding Ms. Green with that?
So what should you do? By all means, if you hate the way your windows look and they are beyond repair and you have money in the bank and return on investment isn’t your first priority, buy new windows. Buy the most energy efficient and attractive windows you can. But if none of those apply, you have several really good options.
First option is to repair your windows so they are fully functional then weatherstrip, caulk, or otherwise seal any leaks in the window’s installation. Next step is to install high quality storm windows, either interior or exterior. In Ms. Green’s house, which is almost a hundred years old and which has beautiful single pane glass six-foot high windows, she has gone with the interior storm option. This option is more expensive but in an older, crookedy house like Ms. Green’s it was the best way to preserve the integrity of the windows.
If your home is newer (and industry statistics say that most replacement windows are being installed in homes newer than ten years old, a statistic that tells Ms. Energy that the window replacement industry is doing a fantastic job at selling their product), then you can easily buy standard storm windows at any home improvement superstore. A quick search shows Ms. Green that it’s possible to buy this kind of storm for about $50. If you install them yourself on your 15 theoretical windows you’ll have spent $750 total, but you’ll have the same basic energy savings you’d have had should you have replaced the windows entirely, but at a 3-year payback.