The energy tax credit now has a $500 lifetime cap for qualified energy efficient upgrades to your existing principal residence, but the deadline is December 31. New homes and rentals do not qualify. You'll find all the details on: http://www.energystar.gov/taxcredits. The highlights:
1. Tax credits for 10% of the cost. You may claim a tax credit of 10% of the cost of certain energy-saving upgrades. These include qualified insulation, windows, roofs, and doors, with a $200 limit for all doors.
2. Tax credits for the full cost. You can claim tax credits for the full cost of specified types of "qualified residential property," but only up to certain caps. For example:
- advanced main air circulating fan – $50
- natural gas, propane, or oil furnace or hot water boiler with annual fuel utilization rate of 95 or greater – $150
- electric heat pump water heater with minimum 2.0 energy factor – $300
- electric heat pump or central air conditioner that achieves the highest efficiency tier of the Consortium for Energy Efficiency – $300 each
- natural gas, propane, or oil water heater that has either a minimum energy factor of 0.82 or a minimum thermal efficiency of 90% – $300
- biomass stove that uses "plant-derived fuel available on a renewable or recurring basis" (see site for details) – $300
Please consult a tax professional before making any purchases you think will qualify for a tax credit.