The Director of Finance shall administer the system of tax credits provided for in this Subdivision. Pursuant to the authority of Section 9-207, Tax-Property Article, Annotated Code of Maryland, there is hereby established a tax credit of one hundred percent (100%) of the County property tax imposed upon commercial property or a single dwelling unit, provided all the requirements of this Subdivision are met. The credit shall be for property taxes on the assessed value of the commercial property or dwelling unit, excluding land, and shall be available to the owner upon application to the Director of Finance. The credit shall be for only one (1) continuous period of time not to exceed one (1) year. To be eligible for the tax credit the dwelling unit or commercial property must comply with the following: A dwelling unit must meet the definition of Subtitle 27 of this Code; A dwelling unit must be assessed as a single unit under the provisions of Title 9, Tax-Property Article, Annotated Code of Maryland, or any rules, regulations, or procedures established thereunder; Commercial property shall be defined as a commercial building, or that portion of a building which has been subdivided as a condominium unit pursuant to Maryland law. The commercial property or dwelling unit is newly constructed or substantially rehabilitated; Substantially rehabilitated means a dwelling unit or commercial property which: Increased in its assessed value by more than fifty percent (50%) solely by reason of its rehabilitation; and Has been rehabilitated because it is more than twenty (20) years old or has been damaged by fire, storm, or other circumstances beyond the control of the owner. The commercial property or dwelling unit has never been sold, rented, or occupied since construction or substantial rehabilitation. The tax credit shall not be applicable to any dwelling unit which has been converted from a rental residential status to a condominium as defined in Title 11, Real Property Article, Annotated Code of Maryland.