Section 43. In addition to its other powers and for the purpose of implementing a program of rental assistance a housing authority may enter into contracts to rent, lease or otherwise provide financial assistance to dwelling units or such other housing units subject to regulations promulgated by the department of community affairs not inconsistent with the standards required for dwelling units for periods of not more that ten years. Any such contract or lease shall contain a provision conditioning the obligations of the housing authority thereunder upon the certification by the housing authority that such dwelling unit or said other housing units are in compliance with the provisions of the minimum standards of fitness for human habitation set forth in the state sanitary code. No housing authority shall enter into any such contract or lease until (a) the housing authority has adopted a scale of maximum rents, including specified utility charges, payable by the authority for housing units of various types under such contracts or leases and the department has approved such scale as being consistent with the purposes of the rental assistance program, (b) the housing authority has determined that an adequate supply of the type of housing to be contracted for or leased is not presently available in the low rent housing projects located within the city or town, and (c) the housing authority has determined that the rent payable under the contract or lease is not in excess of rents payable for similar types of housing units within the city or town. A housing authority shall, in order to encourage the construction and remodeling of dwelling units or such other housing units subject to regulations promulgated by the department of community affairs not inconsistent with the