; and (ii) in which the tariff, net metering, bill credit, or other valuation of solar energy generation, or the sale of that solar generation by a third party, enables a savings-to-investment ratio of at least 1:1 for an eligible entity over a period of not more than 10 years. (B) Use of funds An eligible entity that receives a grant under the program shall use the grant only to pay for— (i) the cost and installation of solar equipment in buildings in which the dwelling units of eligible households are located, including the cost of materials, labor, and permitting; (ii) repairs or upgrades to the buildings described in clause (i) that may be needed to ensure that solar equipment is installed in a safe manner; and (iii) the cost of a community solar subscription. (3) Solar housing loans (A) In general Under the program, the Secretary shall provide loans at zero percent interest— (i) to owners of buildings— (I) that receive assistance under section 8(o) of the United States Housing Act of 1937 ( 42 U.S.C. 1437f(o) ); or (II) with respect to which a credit is allowable under section 42 of the Internal Revenue Code of 1986 for the taxable year in which the loan is provided; and (ii) for the purpose of— (I) installing solar equipment that benefits the dwelling unit of a tenant; (II) if necessary for the installation of solar equipment under subclause (I), making any upgrade to the building in which the dwelling unit is located; and (III) covering the cost of a community solar subscription. (B) Savings (i) In general An owner of a building receiving a loan under this subsection shall— (I) reduce the rent that each tenant described in clause (ii) is required to pay by an amount that is proportional to the savings obtained through any solar upgrades described in subparagraph (A)