Opinion: Vancouver’s move to mandate mechanical air cooling in all new homes is misguided

The authors are researchers from the Climate Change Health Effects, Adaptation, and ResiLience (HEAL) cluster at the University of British Columbia.

Record-breaking temperatures are sweeping Europe and North America, a stark reminder of last summer’s deadly heat dome in British Columbia. More and more it seems that our cities are simply not built to withstand this intense heat.

Until last summer, Vancouver and much of Canada’s west coast were able to remain convinced of the historic climate gifts. While the area does get hot from time to time, it’s nothing like the heat in the east, right? After all, this is one of the last prosperous regions of the world that still uses air conditioning on a massive scale for buildings, at least outside of Europe.

That’s why the City of Vancouver’s move to mandate mechanical air cooling in all new homes by 2025 is of particular concern.

We know that air conditioning is important when it is above 40 degrees Celsius outside, but there is a wide range of heat mitigation measures that are more cost-effective and more conducive to creating healthier buildings and cities, especially considering that such extreme heat is uncommon in Vancouver. In its urgency to address an extreme scenario, the city has missed an opportunity to improve public health while increasing the city’s climate resilience.

Typical air conditioning retrofits in existing residential buildings include installing window units or ‘mini-split systems’ that only recirculate indoor air – in fact, they can reduce the amount of fresh air received indoors to almost zero. New buildings can reduce this with more complex ventilation equipment and control systems, but this comes at a premium that can require cost savings in other parts of a project.

In the 1990s, health scientists and engineering researchers invented a disease called “Sick Building Syndrome,” which was found to affect millions of office workers in North America who pursued their careers in buildings that, while well “conditioned,” were poorly received. natural daylight and little fresh air.

The great solution for the Sick Building Syndrome turned out to be a series of building design measures that probably won’t surprise anyone: If you put people in an indoor space with more direct fresh air, daylight and vegetation, we actually become healthier. Public policies have historically played a critical role in ensuring this is reflected in our building codes and it is worrying that a mandate to install air conditioning in new residential buildings was introduced without tangible mandates to create generally healthier, climate-resilient buildings and communities.

Air conditioning is also not a solution for a ‘net-zero’ future. Singapore, a country whose founder once called air conditioning the greatest invention of the 20th century, has launched several major projects since 2018 to reduce urban overheating and reduce energy consumption for air conditioners.

In Spain and Italy, buildings have been designed for decades with features that naturally reduce the effects of heat, such as exterior shutters on windows. This year, the countries have introduced new energy-saving measures that ensure that indoor spaces cannot be cooled below 27 degrees Celsius. However, Vancouver has set 26 degrees Celsius as the maximum allowable indoor temperature of future homes, a threshold with poor scientific consensus. In countries experiencing warm climates, the new policy aims to reduce reliance on air conditioning. Ironically, Vancouver just set course in the opposite direction.

If we want to survive and hopefully thrive in a warming world, we need our policies to promote many cost-effective solutions with multiple benefits, not to mandate just one technology. Alternative cooling technologies such as radiant systems are a start. These rely on cooling the interior surfaces of our buildings rather than directly cooling the air, providing a comparable degree of comfort with a much lower energy requirement.

We must also prioritize cost-effective passive and ecological forms of cooling that have already been tried and tested elsewhere: our building surfaces and roads must be renovated with materials that reflect more of the sun. Our buildings should be designed to promote better nighttime cooling through natural ventilation. And we need shade on the outside of our buildings, including from trees.

Furthermore, every neighborhood needs at least one outdoor space that stays cool and can serve as a refuge from high temperatures. These spaces also provide citizens with additional year-round benefits as locations for stress relief and social engagement. Our research has clearly shown that areas with more natural vegetation have healthier inhabitants.

We need to rethink how we integrate urban trees into cities, prioritize them and ensure that they too survive the mounting pressures of climate change. This includes protecting existing urban tree canopy during development, proactively managing to keep trees healthy, planting trees in low canopy and heat-sensitive neighborhoods, and involving residents in tree management through activities such as planting and watering. keep trees healthy while reaping the benefits of contact with nature. Unfortunately, Vancouver recently toned down its tree-protection statutes and prioritized housing over urban wildlife.

Cities in Canada need to rethink their action plans when it comes to extreme heat. All mandates for mechanical cooling, such as air conditioning in future or existing buildings, must be accompanied by sensible requirements for passive building design, urban forestry and related climate adaptation measures to cool our cities both indoors and outdoors.

If the global heatwaves of the past two years have shown us anything, it’s that we only have one chance to get it right.

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