The Human Factor | A Little Coolness for a Lot of Heat

During an intense heat wave, the temptation is great to turn on your air conditioner to enjoy a bit of coolness, or to get one. But at what cost to the environment?

“If we tightened the screws on air conditioners, how much CO₂ wouldn’t go into the clouds? », asks Jacques Mercure.

Every summer in Quebec, sales of air conditioners explode. Nearly two-thirds of Quebec households own one today, compared to 54% in 2013, according to Statistics Canada.

But despite the refreshing coolness they provide, air conditioners are not unanimously approved. “It’s a vexing debate,” admits Dr.^r Stéphane Perron, from the National Institute of Public Health of Quebec (INSPQ).

Good for health

In terms of health, numerous studies conducted around the world have shown that air conditioners save lives every year. They reduce the risk of mortality and heat-related health problems, confirms a report published in 2022 by the INSPQ.

In addition, air conditioning helps reduce exposure to contaminants (chemical compounds, spores, mold, pollen) coming from the outside, provided that you keep the windows closed during use, ventilate in parallel and maintain the air well. the device – in particular its filter.

It should be noted, however, that an air conditioner set at too low a temperature can have the opposite effect. Stiff neck, headache, allergic symptoms, dry mucous membranes, thermal shock, cardiovascular problems: when the device is set at less than 20°C, the health risks multiply.

Energy gluttons

Air conditioners also raise several environmental issues.

According to data from Natural Resources Canada, in about twenty years, the energy consumption used to air condition homes has almost doubled – because although new devices are more efficient, more and more households are using them. provide.

According to Hydro-Québec’s calculator, a central air conditioning unit from the 1990s with a capacity of two tons consumes more than 1,500 kWh during the summer. This corresponds to the combined consumption of an electric stove, a dishwasher and a dryer over a year. But a more recent air conditioning unit can consume about half as much.

Calculate your air conditioner consumption on the Hydro-Québec website

A story of gas

Air conditioners pose another challenge: recycling them. They contain a refrigerant gas – just like refrigerators – which circulates in a closed circuit and cools the air. The most dangerous gases, chlorofluorocarbons (CFCs), were banned in 1985 thanks to the Montreal Protocol. They have since been replaced by others, whose environmental impact is lesser, but not negligible.

The problem is that when an air conditioner reaches the end of its life, we tend to leave it on the curb. It can then end up in landfills or be collected by metal dealers who do not necessarily know how to treat these gases. These therefore often end up escaping into the atmosphere.

“If we leave our air conditioner in the street, all the efforts we make for the environment on a daily basis can be cancelled out by this action,” summarizes Jules Foisy Lapointe, general director of GoRecycle.

Mr. Foisy recommends taking your old air conditioner to a GoRecycle collection point, the only organization recognized by Recyc-Québec to ensure the recycling of this type of device, so that these gases are treated and disposed of properly. Currently, the organization estimates that it manages to recover and recycle less than 2 out of 10 air conditioners thrown away in Quebec.

Heat islands… even hotter

Last but not least, you may have felt a warm breeze in an alley where air conditioners line the exterior facade of buildings.

In an article published in 2020 in the journal Environmental Research LettersFrench researchers have shown that, during a heatwave that hit France in 2003, air conditioning helped warm the streets of Paris and its suburbs. Because of this hot air being released outside, some neighborhoods saw the mercury rise up to 3.6 °C higher than if there had been no air conditioners.

For Florent Barbecot, professor in the department of Earth and atmospheric sciences at the University of Quebec in Montreal, this is the heart of the problem.

He emphasizes that this also raises a question of social justice, since it is in disadvantaged neighborhoods that people have less, live in less well-insulated buildings and therefore suffer the most from the heat.

A question of moderation

Several alternatives were proposed by the experts interviewed by The Presssuch as improving the insulation of buildings or creating more green spaces.

“Tree leaves work like mini air conditioners,” says Florent Barbecot. “Except that a tree has no negative environmental impact, it’s free and it brings well-being.”

But in the short term, the most effective solution to cope with heat waves remains to use an air conditioner in moderation – the D^r Stéphane Perron suggests choosing a temperature between 22 and 26°C. This advice is not limited to individuals: around the world, many companies and institutions are committed to being more flexible with air conditioning.

“As climate change progresses, unfortunately, air conditioners are going to be more and more essential. The goal is to try to use them intelligently,” he says.

Read the article “Energy sobriety: museums are rethinking their air conditioning standards”

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