The owner shall provide heat in every habitable room and every room containing a toilet, shower, or bathtub to at least 68°F (20° C) between 7 a.m. to 11 p.m. and at least 64°F (17° C) between 11:01 p.m. and 6:59 a.m. every day other than during the period from June 15th - September 15th, both inclusive, in each year except and to the extent the occupant is required to provide the fuel under a written letting agreement.
The temperature shall at no time exceed 78°F (25° C) during the heating season. The temperature may be read and the requirement shall be met at a height of 5 feet above floor level on a wall any point more than 5 feet from the exterior wall. The number of days per year during which heat must be provided in accordance with 105 CMR 410.000 may be increased or decreased through a variance granted in accordance with the provisions of 105 CMR 410.840 notwithstanding the prohibitions of the 1st clause of the 1st sentence of 105 CMR 410.840(A).
105 CMR 410.000: Minimum standards of fitness for human habitation (state sanitary code, chapter II) can be found on the State of Massachusetts website.
The minimum heating guidelines for public buildings as stated in MGL Section 113, Chapter 149, during the time frame of October 15th to May 15th is listed: