This story has been updated to include comment from The Atmospheric Fund.

Hamilton, Ontario is poised to become one of Canada’s first municipalities to protect renters from dangerous heat waves as it develops a bylaw requiring landlords to install air conditioning in apartments to keep temperatures below 26°C.

On May 15, a public health committee unanimously approved Councillor Cameron Kroetsch’s motion to develop the adequate-temperature bylaw “as quickly as humanly possible,” reports CBC News. Once drafted and approved, the bylaw could be implemented as early as 2024—not a moment too soon for a sweltering Hamilton, projected to become one of Ontario’s hottest cities as the climate crisis deepens.

The port city will be second only to Windsor for heat stress, according to a report by the University of Waterloo’s Intact Centre on Climate Adaptation. Each year, Hamilton could face more than 63 “very hot” days of temperatures above 30°C as early as 2050, and definitely by 2080 in a high-carbon scenario where emissions continue to rise at current rates. Between 1976 and 2005, Hamilton had an average of just 18 such days annually. Even in a scenario where emissions rise till 2050, then quickly decline, researchers predict Hamilton will suffer more than 45 “very hot” days each summer by 2080.

The University of Ottawa’s Human and Environmental Physiology Research Unit recently found that physiological stress begins at a threshold of 26°C when it is sustained for hours, especially among the very young and the elderly.

Tenant advocates at the Association of Community Organizations for Reform Now (ACORN) have been petitioning Hamilton for a maximum heat bylaw since last September. They also want the city to support retrofits at older rental buildings and track heat-related illness and death. City staff have committed to reviewing both demands, reports Global News. The city will also study the feasibility of a program to support low-income tenants with the cost of running air conditioning units, an important service given that some 30% of tenants in Hamilton lack air conditioners, with roughly half of them identifying expense as the barrier, according to [pdf] a recent ACORN survey.

AC will be crucial during heat waves, Jacqueline Wilson, a lawyer with the Canadian Environmental Law Association, told Hamilton’s public health committee.

“Indoor temperatures in apartments can get incredibly hot, and stay incredibly hot, during an extreme heat event, to the extent that it’s dangerous to live in an apartment that does not have active cooling,” she said.

Not Just Air Conditioning

But mandating AC cannot be the only tool in a municipality’s heat adaptation toolbox, wrote Scott Stirrett, an Action Canada fellow with the Public Policy Forum, in a recent Globe and Mail op-ed. Installing mechanical cooling is “an alluring quick fix” that breeds many new challenges, argued Stirrett, who recently co-authored a paper about heat-proofing community housing [pdf].

“Air conditioning can exacerbate climate change through increasing energy use, make people sick by minimizing access to fresh air and natural light, and create a significant ongoing financial burden,” Stirrett wrote. “There are other interventions, which are often less expensive and better for the environment.”

These include adjusting building codes to establish a maximum indoor air temperature, and incentives for building retrofits that increase cooling. It’s also crucial to encourage urban design practices that mitigate the urban heat island, he added.

“Policy-makers should establish local urban tree canopy cover goals, prioritize the installation of a variety of green infrastructure, and ensure a range of land uses in neighbourhoods.”

But setting a maximum indoor air temperature ultimately means some form of mechanical cooling, and much of the discussion still leaves out the transformative potential of heat pumps, which generally deliver about three units of heating or cooling for every unit of electricity they consume. That makes them a far more efficient option than old-style air conditioners—since they can and do operate all year round.

“Given the city’s climate objectives, it would certainly make sense to promote the use of heat pumps to comply with the proposed bylaw,” Bryan Purcell, vice president of policy and programs at The Atmospheric Fund, told The Energy Mix in an email. 

Such promotion should include information and programs to encourage landlord uptake, Purcell said, citing the City of Toronto’s move to provide landlords with low-interest loans, grant support, and technical assistance to install heat pumps as a good act to follow.

Support for landlords “might need to include allowing for more time for compliance, as retrofitting a building with heat pumps requires significantly more planning and construction time than simply putting a window A/C or freestanding AC in each suite,” he added. 

Building Codes: An Urgent Need for Upgrades

After the brutal British Columbia heat dome killed 619 people, mostly seniors, in 2021, the B.C. coroner’s panel identified the urgent need to update building codes.

The review concluded that 98% of those who died last summer were indoors and most victims “lived in socially or materially deprived neighbourhoods” compared with the general population.

The panel recommended updating the provincial building code to require that all new builds have features to combat extreme heat. Passive cooling features like reflective roof tiles, green roofs, and better insulation, and active cooling like heat pumps and AC, must urgently be added to the mix, the report said.

Joanna Eyquem, author of the Waterloo report, said heat has not generally been considered an emergency condition in building codes, but that’s changing.

“Work is under way nationally to develop standardized requirements to address overheating in new construction,” said Zachary May, executive director of the Building and Safety Standards Branch of B.C.’s Ministry of Housing.

But Eyquem and Stirrett also warn against waiting around for perfect building codes, not least because they only affect new builds, doing nothing to help the people enduring life-threatening summer days and nights in older rental units. The vast majority of housing that Canadians will inhabit in 2050 has already been built.

A Canadian First

In her deposition to the public health committee, Wilson pointed out that Hamilton’s proposed max-heat bylaw will be the first of its kind in Canada if it passes. It would also be among the first of its kind in North America, though cities like Tempe, Arizona, Dallas, Texas, and Montgomery County, Maryland require landlords to provide air conditioners for their tenants, says ACORN.

Such a mandate could have been possible for California. But Bill 2597, which would have required residential units to maintain adequate cooling, failed to pass. It sparked opposition from rental industry lobbyists whose clients would have been forced to provide cooling. They played a pivotal role in killing the bill with the caution that the increase in air conditioning would collapse the state power grid.

“But contrary to some of their claims, the legislation would not mandate air conditioners in every housing unit,” the LA Times explained in an editorial. “Rather, it would have directed officials to craft statewide standards for safe indoor temperatures, which could include air conditioning or energy-efficient heat pumps where necessary, but could also be achieved through improved insulation, solar reflective cool roofs, ventilation, shade trees, and other measures, depending on the local climate and specific site conditions.”