What date must landlord turn heat on and off in Philadelphia Pa.

It depends on the size of the apartment and how many units are in the complex. However, the City of Philadelphia Department of L&I states: In buildings with two or more apartments, the landlord must supply heat at a temperature of 68 degrees for each apartment from October 1 through April 30 and during May and September when the outside temperature falls below 60 degrees. See the link for L&I's pamphlet on housing in Philadelphia. Those requirements are also found in the City Code at PM-406.2.