Loans from the Fund may be used for: the purchase and installation of a qualifying energy system, including any necessary ancillary machinery, equipment, or furnishings; technical assistance for the planning and installation of a qualifying energy system; and actions that improve energy efficiency, such as repairing or replacing windows, doors, and heating, ventilation, and air–conditioning systems and other similar improvements. Each borrower for a loan under subsection (a)(1) or (3) of this section shall contribute at least 10% of the cost of the qualifying energy system or energy efficiency action. Loans made under the Program shall be repayable by the borrower in accordance with a schedule set by the Center. The schedule set by the Center may be on a deferred payment basis. A borrower shall provide assurances for the repayment of a loan. The assurances: shall include a promissory note; and may include a plan for repayment. Loans may be made in conjunction with or in addition to financial assistance provided through other State or federal programs.