Utility Energy Service Contracts Improvement Act of 2013 - Amends the National Energy Conservation Policy Act, with respect to promotion of the conservation and efficient use of energy and water, and the use of renewable resources, by the federal government, to authorize each agency to use measures provided by law to meet energy efficiency and conservation mandates and laws, including through utility energy service contracts.
Authorizes the term of such a contract to have a contract period that extends beyond 10 years, but prohibits such term from exceeding 25 years.
Requires the contract conditions to include requirements for measurement, verification, and performance assurances or guarantees of the savings.