You can't claim Energy Star appliances or water-saving improvements like low-flow toilets, low-flow shower-heads, or xeriscaping on your federal return. However, many state and local governments and utility companies offer incentives or rebates for energy- or water-saving home improvements. An online search will reveal what your state has to offer (for example, you might search for Arizona toilet rebate, California water saving incentives, etc.).
Under the Residential Energy Efficient Property Credit, you can get a federal tax credit in 2018 for installing alternative energy equipment, such as solar electric property, solar water heaters, geothermal heat pumps, small wind turbines, and fuel cell property.
The federal $500 Nonbusiness Energy Property Tax Credit for energy-efficient improvements like windows, doors, skylights, insulation, roofing products, nonsolar water heaters, heating, ventilating, and cooling systems wasn't renewed for tax year 2018.