Usually the responsibility is agreed upon in the lease. Whenever a dwelling is heated by means of a furnace, boiler or other heating apparatus under the control of the owner or operator of the dwelling, such owner or operator, in the absence of a written contract or agreement to the contrary, shall be deemed to have contracted, undertaken or bound himself or herself to furnish heat in accordance with the provisions of this subsection to every dwelling unit which contains radiators, furnace heat duct outlets or other heating apparatus outlets. (Please see Section 12-8.17b of the Revised General Ordinances of the City of Trenton for details.)