The tax credit for energy efficient improvements made to a home are a set 30% of the cost, up to a total maximum of $1,500 for the following products: windows (including storm windows and skylights), doors (including storm doors), insulation, roofs (asphalt and metal), HVAC, non-solar water heaters, and biomass stoves. Each of these must meet certain guidelines set forth by the government. A summary of specifications is available at www.energystar.gov. This means that all the projects you complete can give you a total credit of $1,500; this is not an amount that applies to each project. There are also a few other rules that apply to home improvements. They must be made on a taxpayer's primary residence, and they must be ready for use sometime between January 1, 2009 and December 31, 2010. You must also obtain a Manufacturer Certification Statement, which is a signed statement from the manufacturer that the product qualifies for the tax credit. Other improves also earn a tax credit of 30% of the cost with no limit. These products are the following: solar panels, solar water heaters, geothermal heat pumps, small wind energy systems, and fuel cells.