New Windows: Are They Worth It?

Mon, 2010-04-05 08:21

Here’s the pitch:

“Your old, leaky windows are sucking heat and energy out of your house. Keeping those ancient money hogs is like throwing your hard-earned dollars in the trash. Install shiny, new, energy-efficient units in your walls, and all your energy bill will be slashed in half.”

This message is conveyed to us in commercials, magazine articles, political speeches, and by that guy in the home improvement store.

Tax incentives, rebates, increased home values - sometimes it seems like everyone from politicians to Realtors to the power companies have become experts on energy efficiency. With so much hype touting the benefits of new windows and trying to convince you to spend thousands of dollars on their installation, it is reasonable to step back and ask the question: “Are they worth it?”

Let’s start with the fact that replacing old, leaky windows with new, efficient ones will certainly result in lower energy use. However, that fact can be misleading. There are many home improvements that will result in lower energy use, and windows are just one possibility. Making improvements to our homes is an investment, and, like any investment, the trick is figuring out which measures will give us the greatest return.

When thinking about reducing energy use in the home, it is important to consider where the greatest amount of energy is lost. Air leakage accounts for the lion’s share of the loss. Heat travels in the air, and when air is allowed to escape, the heat goes with it. When we examine the various ways that air escapes from the home, we find that windows only account for about 10% of the overall loss. Factors such as penetrations in the walls and ceilings, leaky ductwork, and poorly functioning chimney flues make up the other 90%.

A complete air sealing and insulation package that will address much of that 90% can cost as little as a few thousand dollars and perhaps, if tackled by an enterprising homeowner, in the hundreds of dollars. New windows, on the other hand, usually average above ten thousand dollars.

A home can save as much as a few hundred dollars per year in energy costs with air sealing and upgraded insulation. Recent studies find the average savings with new windows is about 40 dollars.

When viewed in terms of investment, the payback period on air sealing and insulation can be as low as a couple of years. Most window upgrades won’t see a monetary payback in the lifetime of the home.

You can do the math. Replacing your windows may improve the look of your home, they may even increase your enjoyment of your home as you slide open that smoothly operating sash. However, if you are looking to save money by investing in new windows, you might do well to look elsewhere.