RSA 451-C:16: Savings Clause.

All rental agreements, entered into before the effective date of this chapter which have not been extended or renewed after that date, shall remain valid and may be enforced or terminated in accordance with their terms or as permitted by any other law of this state. Nothing in this chapter shall be construed to impair or affect the right of the parties to create additional rights, duties, and obligations in and by virtue of the rental agreement.