A bylaw named for what it does
Section 1.1 gives the short title: the Rented Dwelling Temperature By-law. Unlike most municipalities, Ajax keeps heat and cooling in a single instrument aimed squarely at rented dwellings rather than folding them into general property standards.
Section 2.1(a): adequate and suitable heat means "a minimum air temperature, in the part of the accommodation which is normally heated, of at least 20 degrees Celsius", and "Portable heaters may not be utilized to achieve adequate and suitable heat".
Section 3.1 attaches the season, in the same words its neighbours use: the landlord of every rented dwelling normally heated by or at the expense of the landlord shall maintain adequate and suitable heat "between the 15th day of September in each year and the 31st day of May in the following year".
The signed-lease qualifier on cooling
Section 3.2 applies the cooling duty to a unit "equipped with a Central Air Conditioning System by signed lease" — a narrower trigger than simply having a system installed.
Section 2.1(b) defines that system as a mechanical one that cools from a central location and distributes by fans and ductwork, and expressly excludes portable units and window shakers. Section 2.1(e) then caps suitably cooled air at 26 degrees.
So in Ajax the cooling obligation follows the lease document. What the tenancy agreement says about air conditioning is the thing that decides whether section 3.2 bites, which makes the lease worth drafting carefully rather than inheriting.
The 2026 replacement
By-law 19-2026 repeals 47-2017. If you are working from a template, a checklist, or advice written before 2026, the instrument it names is no longer the operative one, even where the numbers happen to match.
Ajax and Whitby run closely parallel drafting, which is common among neighbouring Durham municipalities. The 20 degrees and the September 15 to May 31 season are shared; the cooling trigger is not, and Whitby's bylaw additionally names additional dwelling units and sets a hot water floor.
For a landlord with units across Durham the practical answer is to run the stricter reading everywhere rather than maintain two operating procedures.