The Nonbusiness Energy Property Credit expired after tax year 2017.  This credit was for certain high-efficiency heating and air conditioning systems, water heaters and stoves that burn biomass, energy-efficient windows and skylights, energy-efficient doors, qualifying insulation and certain roofs.

As of this date the Congress has not renewed the Nonbusiness Energy Property Credit for tax year 2018.

The Residential Energy Efficient Property Credit is in effect for 2018 to the end of 2021 - 

Qualified solar electric property, Qualified solar water heating property, Qualified small wind energy property,  Qualified geothermal heat pump property and Qualified fuel cell property costs.