N.H. Rev. Stat. § 374-D:11
Any municipality having bonds outstanding under this chapter, when authorized by a 2/3 vote as prescribed in RSA 33, may issue refunding bonds for the purpose of paying bonds issued by or on its behalf, at maturity or upon acceleration or redemption. The refunding bonds may be issued in sufficient amounts to pay or provide the principal of and any redemption premium on the bonds being refunded, any interest accrued or to accrue to the date of payment of such bonds, the expenses of issue of the refunding bonds, the expenses of redeeming the bonds being refunded, and such reserves for debt service or other capital or current expenses from the proceeds of such refunding bonds as may be required by a trust agreement or resolution securing bonds or notes. The issue of refunding bonds, the maturities and other details of them, the security for them, the rights of the holders of them, and the rights, duties, and obligations of the municipality with respect to them shall be governed by the provisions of this chapter relating to the issue of bonds other than refunding bonds insofar as the same may be applicable, provided that the period from initial issuance of a series of bonds or notes until the final maturity of any refunding issue shall not exceed 50 years.
RSA 374-D:11
1981, 545:6, eff. Aug. 29, 1981.