There’s good news to come out the fiscal cliff deal for homeowners looking to retrofit their existing homes with more efficient HVAC equipment or install high-efficiency systems in their new homes. The 25C energy tax credits, which expired at the end of 2011, are back on for heating and cooling equipment, as well as water-heating systems. Take upgrades a step further and you can get tax credits for upgrades to the home’s structure. Find out what equipment and materials qualify for the credits, and the general guidelines you must follow.