I stumbled across an article the other day that told how to save on energy and get a tax credit all at the same time. Some of the things you can do is add energy effecient appliances, water heaters, heating and cooling systems, windows and doors, insulation and roofing projects. It is possible to get a credit of 30% of the cost up to $1,500.00. Of course it has to be your primary residence that you make these changes to.
Here are some quick links I found: http://www.geappliances.com/energy-star-appliances/water-heater.htm