* There is no maximum credit for systems placed in service after 2008. The maximum credit is $2,000 for systems placed in service in 2008.
* Systems must be placed in service on or after January 1, 2008, and on or before December 31, 2016.
* The geothermal heat pump must meet federal Energy Star program requirements in effect at the time the installation is completed.
* The home served by the system does not have to be the taxpayer’s principal residence.

Residential Renewable Energy Tax Credit
Incentive Type: Personal Tax Credit
Eligible Renewable/Other Technologies: Solar Water Heat, Photovoltaics, Wind, Fuel Cells, Geothermal Heat Pumps, Other Solar Electric Technologies
Applicable Sectors: Residential
Amount: 30%
Maximum Incentive: Solar-electric systems placed in service before 2009: $2,000
Solar-electric systems placed in service after 2008: no maximum
Solar water heaters placed in service before 2009: $2,000
Solar water heaters placed in service after 2008: no maximum
Wind turbines placed in service in 2008: $4,000
Wind turbines placed in service after 2008: no maximum
Geothermal heat pumps placed in service in 2008: $2,000
Geothermal heat pumps placed in service after 2008: no maximum
Fuel cells: $500 per 0.5 kW
Carryover Provisions: Excess credit may be carried forward to succeeding tax year
Eligible System Size: Fuel cells: 0.5 kW minimum
Equipment/Installation Requirements: Solar water heating property must be certified by SRCC or by comparable entity endorsed by the state in which the system is installed. At least half the energy used to heat the dwelling’s water must be from solar. Geothermal heat pumps must meet federal Energy Star requirements. Fuel cells must have electricity-only generation efficiency greater than 30%.
Authority 1: 26 USC § 25D
Date Enacted: 8/8/2005 (subsequently amended)
Date Effective: 1/1/2006
Expiration Date: 12/31/2016
Authority 2: IRS Form 5695 & Instructions: Residential Energy Credits

Learn more here about the Federal Tax credits.