Every unit of dwelling space shall contain facilities to provide heat sufficient to maintain a minimum inside temperature of at least 68 degrees Fahrenheit in all habitable rooms, measured at least one foot away from any surface at the coldest portion of the space subject to regular use by occupants of any such room when the outside temperature is at design winter conditions. This provision shall not apply to units of dwelling space which are neither occupied nor intended to be occupied between October 1 and the next succeeding May 15.
N.J. Admin. Code § 5:10-14.1