N.H. Rev. Stat. Ann. § 33:5-d

The terms of repayment by a municipality of any loan from the loan fund established under RSA 486:14, or from any other state revolving loan fund established for water pollution control, solid waste disposal or treatment or other environmental improvement purposes, shall be governed by the statute and rules establishing the loan fund, notwithstanding any inconsistency with the provisions of this chapter relating to required annual installments, maximum period, or other such terms and conditions. In addition, a municipality may use proceeds of such a loan to pay interest on the loan during construction and for a period thereafter to the extent permitted by such statute or rules, and no authenticating certificate shall be required under RSA 33:11 on any bond, note or other document evidencing the loan.