Md. Code, Tax - General § 11–409

Notwithstanding any other provisions of law, before a State agency issues a rebate or similar instrument or authorizes a rebate or similar instrument to be issued by a nongovernmental entity to reduce the cost of a retail sale of household appliances under a program to promote energy efficiency, the State agency or nongovernmental entity shall require the buyer of a household appliance to certify that:

(1) the household appliance was purchased at a retail sale in the State; or

(2) the buyer paid the applicable State sales and use tax.