As of December 31, 2011, many tax credits that were available for the purchase of energy-efficient products have expired. This had included such items as windows and doors, insulation, air conditioners, and propane water heaters. If you are, however, thinking about installing a new heating and air conditioning system, a geothermal heat pump, solar panels, a solar water heater, a small wind power generation system, or a fuel-cell there are still some very nice tax credits available through 2016 that could really help offset any initial cost.
After 2016 there are no more tax credits, unless new legislation is introduced, for any consumer high energy efficiency based products. Learn more.