The landlord must provide running water, reasonable amounts of hot water and reasonable heat, unless 1) the building is not required by law to be equipped for that purpose, or 2) where the unit is equipped with appliances that generate heat and hot water and these appliances are within the exclusive control of the tenant. Finally, the landlord must keep in reasonably good and safe working order and condition all electrical, gas, plumbing, sanitary, heating, ventilating, air conditioning and other facilities and appliances supplied, or required to be supplied by him. The landlord and tenant may agree in writing for these duties to be performed by the tenant if that agreement is entered into in good faith. Appliances present in the dwelling unit are presumed to be supplied by the landlord unless specifically excluded in the lease.