Replace Old Windows with Energy-Efficient Models

If your windows are more than 15 years old, you may be putting up with draftiness, windows that stick in their frames, and skyrocketing energy bills. Energy-efficient windows would be a great improvement, but replacement can be very expensive. In a 2007 survey conducted by Consumer Reports, half of respondents spent $8,000 or more to replace all the windows in their homes, and 16% shelled out $15,000+.

Windows recoup much of their cost

The range for energy-efficient window pricing is wide, but Energy Star-qualified windows start around $120 for a 36” x 72” single-hung window and can go up 10 times that. With labor, you’re looking at about $270 to $800+ per window. Typically, windows at the low end of the price spectrum are less energy efficient.

But that doesn’t mean the numbers can’t make sense for you. For starters, window replacement is one of the best home remodeling projects in terms of investment return: For vinyl windows, you can recoup about 75% of the project cost in added home value, according to Remodeling Magazine’s annual Cost vs. Value Report.

Based on the projects outlined in Cost vs. Value, that’s a value add of about $8,200 to $10,600. Plus, if you choose windows that qualify for the new federal tax credit (U-factor and solar heat gain coefficient ratings must be 0.3 or less), you can effectively lop $1,500 off the purchase price.

You’re also likely to see modest savings on your energy bill. In general, you’ll save $126 to $465 a year if single-pane windows in a 2,000-square-foot house are replaced with tax-credit-eligible windows, according to the Efficient Windows Collaborative, a coalition of government agencies, research organizations, and manufacturers that promotes efficient window technology.

Keep in mind, though, that the savings can vary widely by climate, local energy costs, and the energy efficiency of both the windows purchased and the windows being replaced. Finally, you may qualify for low-interest loans or other incentives offered by your local utility that can sweeten the deal.

Sample costs, incentives

Here’s a hypothetical situation to help frame your purchase decision:

Location: Des Moines, Iowa

Old windows: Double-pane, non-Energy Star windows

New windows: Energy Star-qualified, tax credit-qualified vinyl windows

Purchase price plus installation: $10,500

Subtract tax credit: -$1,500

Subtract local utility rebate for installing Energy Star replacement windows (12 windows, $25 each): -$300

Net price: $8,700

The Des Moines homeowner could recoup about 70% of the project cost at resale, according to estimates in Cost vs. Value. From a net price of $8,700, the owner has “lost” only $1,350.

And his annual energy savings will be $91. Had the original windows been single-paned non-Energy Star, his annual savings would be $385. Double-paned windows are more common.

Evaluate price vs. energy efficiency

The range for energy-efficient window pricing is wide, but you can expect to pay about $500-$1,000, including installation per window. The most efficient windows on the market are usually the most expensive, but it’s not necessary to buy the highest-end products to realize utility bill savings or improve comfort and aesthetics. So how do you choose the most energy-efficient models for the price?

Thanks to Energy Star, you really don’t have to, according to Nils Petermann, project manager for the Efficient Windows Collaborative. Energy Star labels will tell you whether a window performs well in your climate based on ratings from the National Fenestration Rating Council.

However, if you’re looking for windows that qualify for the $1,500 federal tax credit, make sure the U-factor and SHGC are both less than or equal to 0.3 regardless of climate zone. Not all Energy Star windows qualify.

Know the language of windows

It’s also helpful to familiarize yourself with terms that appear on many window labels:

Glazing is simply the glass used in the window. The number of layers of glazing (single, double, or triple) don’t necessarily equal greater efficiency; the presence or absence of the other items in this list affects a window’s total energy performance, says Petermann. Glazing coatings can substantially affect a window’s U-factor, or degree of insulation against the outdoors.

Low-E stands for low emissivity, the window’s ability to reflect rather than absorb heat when coated with a thin metallic substance. Low-E coatings add up to 10% to the price of a window.

If your windows are in relatively good shape but you’d like better insulation, you can buy and apply Low-E films to your windows. They’re effective, but not as much as those put between glazing layers during manufacture. Look for the NFRC rating on these films, Petermann says. Low-E films start at about 50 cents per square foot, but you may want to check into the cost of having them professionally installed for large or complicated applications.

Gas fills typically consist of argon or krypton gas sandwiched between glazing layers to improve insulation and slow heat transfer. They often won’t work at high altitudes because differences in air pressure cause them to leak out.

Spacers separate sheets of glass in a window to improve insulating quality; the design and material are important to prevent condensation and heat loss.

Frame materials include vinyl, wood, aluminum, fiberglass, and combinations of. They each have different strengths: Vinyl windows are good insulators and are easy to maintain, but contract and expand with temperature changes, affecting the window’s air leakage; wood offers a classic look but is similarly affected by moisture changes and needs regular maintenance; fiberglass is very stable and low-maintenance but can be expensive; and aluminum is lightweight, stable, and a good sound proofer but is a rapid conductor of heat, making it a drain on energy efficiency.

Karin Beuerlein has covered home improvement and green living topics extensively for HGTV.com, FineLiving.com, and FrontDoor.com. She has also written for dozens of national and regional publications in more than a decade of freelancing, including Better Homes & Gardens, The History Channel Magazine, Eating Well, and Chicago Tribune. She and her husband started married life by remodeling the house they were living in. They still have both the marriage and the house, no small feat.