§ 487-a. Exemption from taxation of conservation improvements to certain residential premises. Insulation and other energy conservation measures hereafter added to one, two, three or four family homes, which qualify for (a) financing under a home conservation plan pursuant to Article -A of the public service law, or (b) any conservation related state or federal tax credit or deduction heretofore or hereafter enacted, shall be exempt from real property taxation and special ad valorem levies to the extent of any increase in value of such homes by reason of such addition.