Home improvement tax credits are now available for home improvements “placed in service” from January 1, 2009 through December 31, 2009. Any qualified home improvements made in 2008 are not eligible for the tax credit.

Home improvement tax credits are available for insulation, replacement windows, water heaters, certain high efficiency heating and cooling equipment, and biomass stoves. See chart. The maximum amount that a taxpayer may claim from all of these tax credits combined is $500 over the lifetime of the tax credit (2006, 2007 & 2009).

If you are building a new home, you can qualify for the tax credit for photovoltaics, solar water heaters, small wind systems and fuel cells, but not the tax credits for windows, doors, insulation, roofs, HVAC, or non-solar water heaters. More.

The Internal Revenue Service (IRS) guidance for consumers: IRS Notice 2006-26 

Starting January 1, 2009, there is a new tax credit for Plug-in hybrid electric vehicles, starting at $2,500 and capped at $7,500 for cars and trucks (the credit is based on the capacity of the battery system). The first 250,000 vehicles sold get the full tax credit (then it phases out like the hybrid vehicle tax credits).

Tax credits are available to buyers of hybrid gasoline-electric, diesel, battery-electric, alternative fuel, and fuel cell vehicles. The tax credit amount is based on a formula determined by vehicle weight, technology, and fuel economy compared to base year models. These credits are available for vehicles placed in service starting January 1, 2006. For hybrid and diesel vehicles made by each manufacturer, the credit will be phased out over 15 months starting after that manufacturer has sold 60,000 eligible vehicles. For vehicles made by manufacturers that have not reached the end of the phase-out, the credits will end for vehicles placed in service after December 31, 2010. See the IRS Website for updated information 

Tax credits are available for qualified solar water heating and photovoltaic systems. The credits are available for systems “placed in service” from January 1, 2006 through December 31, 2016. The tax credit is for 30% of the cost of the system, up to $2,000. After December 31, 2008, this $2,000 cap will be removed for photovoltaic systems (but not solar water heaters). This credit is completely separate from the $500 home improvement credit.

Tax credits are available to homeowners who install residential small wind turbine systems. The credits are available for systems placed in service from January 1, 2008 to December 31, 2016. The tax credit is for 30% of the cost of the system, up to $500 for each half kilowatt of capacity with an overall maximum of $4,000.

There is a consumer tax credit of up to 30% of the cost (up to $1,500 per 0.5 kW of capacity maximum) for installing a “qualified” fuel cell and microturbine systems. The credits are available for systems “placed in service” from January 1, 2006 through December 31, 2016. This credit is not limited to the $500 home improvement cap.