Ask the expert

LITTLE ROCK — I am planning to replace the windows and possibly doors in my home for something more energy efficient. I understand I might be able to get a tax credit. Please fill me in.

Section 1121 of the American Recovery and Reinvestment Act of 2009 - the stimulus package - allows homeowners a federal energy tax credit of 30 percent of the cost of replacement windows and doors for their homes. The maximum tax credit is $1,500 per homeowner for all improvements combined. It applies during the taxable years 2009 and 2010.

The tax credit is for the price of the product only and does not include the cost of installation, says improvement and real estate columnist Al Heavens of The Philadelphia Inquirer. To qualify, windows and doors must have a 0.30 U-factor and 0.30 or better solar heat-gain coeffi cient.

Here are a few more words of explanation, says Heavens, courtesy of the U.S. Department of Energy:

The U-factor is the rate at which a window, door, or skylight conducts nonsolar heat flow - typically expressed in British Thermal Units per hour minus feet squared minus temperature in degrees Fahrenheit.

For windows, skylights, and glass doors, a U-factor may refer to the glass or glazing alone. But the National Fenestration Rating Council's U-factor ratings represent the entire product's performance, including frame and spacer material. Basically, the lower the U-factor, the more energy-efficient the window, door, or skylight. (Fenestration is the arrangement of windows in a building.)

A solar heat-gain coeffi cient refers to a fraction of solar radiation admitted through a window, door, or skylight - either transmitted directly and/or absorbed, and subsequently released as heat inside a home.

The lower the coefficient, the less solar heat the door, window, or skylight transmits and the greater its shading ability. A product with a high coefficient is more effective at collecting solar heat gain during the winter. A product with a low rating is more effective at reducing cooling loads during the summer by blocking heat gained from the sun.

Therefore, the solar heat-gain coefficient you need for a window, door, or skylight should be determined by such factors as your climate, orientation, and external shading.

Here in Arkansas, the best bet is usually for a low solar heat-gain rating to cut cooling costs during the summer.

What you want to look for are Energy Star-qualifi ed windows and doors, which reduce energy bills about 7 percent to 24 percent.

(Energy Star is a joint program of the U.S. Environmental Protection Agency and U.S. Department of Energy to promote energy effi ciency.) Many of the qualifi ed windows anddoors have a special coating on the glass that acts like a sunscreen, helping protect fabrics, upholstery, art, etc. from fading.

The energystar.gov Web site offers a more detailed explanation of what does and doesn't qualify for tax credits. It also provides descriptions of what increases energy effi ciency in doors and windows.

To get the tax credit, retain receipts that show the cost of the qualifying products (again, without the installation charges), and save each National Fenestration Rating Council (NFRC) label from each window or door. Keep these with your tax materials in case of audit. The manufacturer may have a certifi cation statement to keep with tax records, too. Submit the claim with your taxes for the year the windows and/or doors were installed.