As of 2015, the federal government offers tax credits for geothermal heat pumps, residential wind turbines and solar energy systems, states Energy Star. There is no restriction on new or existing constructions. However, the tax credit does not apply to rentals.
These tax credits cover anywhere from 30 percent to the complete cost of the system, states Energy Star.
The requirements to receive tax credits for geothermal heat pumps range from an energy efficient ratio (EER) of 16 to 21.1, depending on the type of geothermal heat pump (water-to-air, water-to-water or direct expansion), explains Energy Star. The required coefficient of performance (COP) ranges from 3.1 to 4.1.
To receive a federal tax credit for residential wind turbines, the turbines must have a nameplate capacity of no more than 100 kilowatts, states Energy Star. Solar water heaters must generate at least 50 percent of the property's energy from the sun. They also must have certification from the Solar Rating and Certification Corporation or a similar entity approved by the government.
The federal government also gives tax credits for residential fuel cells and microturbine systems, reports Energy Star. However, these tax credits are only available for the taxpayer's principal residence. Fuel cells must have an efficiency rating of at least 30 percent and capacity of 0.5 kilowatts.
In addition, some Energy Star products qualify for a rebate. As of 2015, Energy Star provides a current and searchable list of applicable products on its website.