Every owner and operator of any building who rents, leases or lets one or more dwelling unit, rooming unit, dormitory or guestroom on terms, either express or implied, to furnish heat to the occupants thereof shall supply heat to the occupants thereof shall supply heat during the period from October to April to maintain a room temperature of not less than sixty-eight (68) degrees F. (20 degrees C.) in all habitable rooms, bathrooms, and toilet rooms. (602.3)
Exceptions:
(A) When the outdoor temperature is below the winter outdoor design temperature for the locality, maintenance of the minimum room temperature shall not be required provided that the heating system is operating at its full design capacity. The winter outdoor design temperature for the locality shall be as indicated in Appendix D of the International Plumbing Code.
(B) In areas where the average monthly temperature is above thirty (30) degrees F. (-1 degrees C.) a minimum temperature of sixty-five (65) degrees F. (18 degrees C.) shall be maintained.