http://www.energystar.gov/index.cfm?...pr_tax_credits
Tax Credits for Homeowners:
There are different levels of credit depending on the type of
improvement made, but the maximum amount of homeowner credit for all
improvements combined cannot exceed $500 during the two year period of
the tax credit. This tax credit applies to improvements made from
January 1, 2006 through December 31, 2007.

Eligible measures a

Added insulation to walls, ceilings, or other part
of the building envelope

Replacement windows

High-efficiency gas, oil, and propane furnaces and
boilers

High-efficiency central air conditioning units,
including air-source and ground-source heat pumps

High-efficiency fans for heating and cooling
systems

High-efficiency water heaters, including heat pump
water heaters

Incentive amounts a

Added insulation: 10% of cost up to $500

Replacement windows: 10% of cost up to $200

Furnaces and boilers: $150 for qualifying units

Central air conditioning units: $300 for
qualifying units

Fans for heating and cooling systems: $50 for
qualifying units

Water heaters: $300 for qualifying units

ENERGY POLICY ACT OF 2005
DRAFT SUMMARY OF TAX CREDITS FOR HOMEOWNERS¹
(US Treasury has not yet provided final interpretation for IRS use)