§ 135-m. Applicability to prior installations. In the event any eligible customer installs energy conservation measures subsequent to the effective date of this act, but prior to the adoption of a home conservation plan by his gas or electric utility, and the work performed or obtained by such eligible customer would qualify for financing under a subsequently adopted plan, such eligible customer shall be eligible for retroactive financing and participation in the plan adopted by his utility in accordance with the provisions of this article.