To lease, with or without an option to purchase, for a period not to exceed 5 years or purchase under an installment contract extending over a period of not more than 5 years, with interest at a rate not to exceed 6% per year on the unpaid principal, such apparatus, equipment, machinery or other personal property as may be required when authorized by the affirmative vote of 2/3 of the members of the board. To lease for a period not to exceed 20 years such rooms, buildings and land, or any one or more of such items, as may be required when authorized by the affirmative vote of 2/3 of the members of the board. The provisions of this Section do not apply to guaranteed energy savings contracts or leases entered into under Article V-A.