Low-Income Solar Act This bill requires the Department of Energy to establish a loan and grant program for photovoltaic solar (a method of converting energy from the sun into electricity) installations in low-income and underserved areas for FY2018-FY2032. Loans must be provided for: (1) community solar facilities that provide solar energy to low-income households, or (2) solar installations at federally subsidized affordable housing at multi-family complexes. The community solar facilities must: (1) be owned by an organization of electricity consumers that own a share of the facility's solar electricity generation, (2) have a certain a nameplate rating (or power generation capacity), (3) be located in or near a community that uses the electricity generated by the facility, and (4) reserve at least 25% of the electricity generated for low-income households. Grants must be given for: (1) solar electricity generating facilities installed on properties of eligible, low-income home owners; or (2) new solar projects for low-income households and individuals, including the costs of equipment and job training associated with solar projects.