; or (B) the weatherization assistance program established under part A of title IV of the Energy Conservation and Production Act ( 42 U.S.C. 6861 et seq. ). (2) Other sources To the maximum extent practicable, a State receiving financial assistance under subsection (b) shall implement, improve, or expand a State energy savings performance contracting program by primarily using private financing, public financing, or any other source of Federal or non-Federal funds. (3) Return of unused funds A State that receives financial assistance under subsection (b) but does not expend those funds within 5 years of receipt of the funds shall return the unexpended funds to the Secretary. (d) Allocation In providing financial assistance to States under subsection (b), the Secretary shall— (1) to the maximum extent practicable, allocate funds made available for that purpose— (A) in accordance with the formula described in section 420.11 of title 10, Code of Federal Regulations (as in effect on January 1, 2021); and (B) during the fiscal year for which the allocation is made