My sister is the second owner of her house in northwest Washington, D.C. She bought it from the widow of the man whose construction company built it in 1929. Because it was his own house, he gave it lots of personal attention, including a giant cedar-lined walk-in closet and Craftsman-style interior trim. From the time it was built to the day my sister bought it, the house suffered through five decades of passing fads, including one that led to the replacement of the front door and another to the covering of the hardwood flooring — with linoleum in the kitchen, and elsewhere in the house with bright red wall-to-wall carpeting.

My sister pulled up the carpeting and refinished the underlying hardwood flooring. She added central air and finished the basement. But she never got around to doing anything about the front entry door. The original multi-paned sidelites and transom were intact, but the half-glass wood paneled door had been replaced with a plain insulated steel blank mounted on a skinny metal jamb. Every winter since moving in, my sister has complained about the drafty front door, but competing demands kept her from doing anything about it.

Until last month, that is, when two factors came together to motivate her to replace the door: first, the entrance lockset stopped working, making the door practically useless; and second, the cost of a new door dropped by $1,500, the amount of the tax credit she could receive through the American Recovery and Reinvestment Act of 2009.

The ARRA is designed to inject more than $780 billion into the economy over the next several years, including paying for tax credits to homeowners who make qualified energy-related home improvements. So we’ve devoted this entire issue to explaining, in detail, everything remodelers need to know about the ARRA tax credits. You’ll find the latest IRS rulings on the credits, tips on sales and marketing, details about additional state or utility funding, as well as articles about bringing trade contractors onboard, avoiding legal pitfalls, and more. We provide the information you need to explain the credits to homeowners who just might be interested in hiring you to handle the work.

When my sister’s door salesman’s phone started ringing off the hook in May, he didn’t have answers for all of the callers’ questions about tax credits. When your phone starts ringing, you’ll have this issue.

Problem solved.