With all the work that goes into undertaking a home improvement—planning, financing, hiring a certified contractor, and getting a permit, not to mention the inevitable delays and problems you'll face—your project to boost the energy efficiency of your home will likely take a lot longer than you'd expect. So don't delay if you want to take advantage of the federal tax credits for energy-efficient home improvements, since many of the credits will expire by the end of 2010.

Combine incentives
Pairing a federal credit with state and local utility incentives can save you even more. If you're planning to install an air-conditioning system now, for instance, combine the 30 percent credit for split-ductless and central-air systems with state and local utility incentives and cash for appliance rebates. Also look for the biggest payback. The last column of the chart on this page provide estimates of annual savings.

Mind the $1,500 cap
For the entire 2009-2010 period, you can't claim more than a total of $1,500 in federal tax credits on improvements. If you're getting the full $1,500 tax credit in 2009, you are not eligible for a tax credit on these products in 2010.

You can, however, combine the credits expiring in 2010 with those that are running until 2016 for geothermal heat pumps, solar water heaters, solar- and wind-energy systems, and fuel cells. Visit this page from the U.S. Department of Energy's EnergySavers.gov for specifics on the credits.