As climate change drives hotter temperatures, our first impulse to keep cool, especially in our homes, is to turn on the air conditioner.

In 2009, 50 per cent of Canadian homes reported having some type of air conditioning system, whether central or standalone air conditioning. By 2017, that number had risen to 60 per cent. The percentage of households with air conditioning is highest in Ontario (83 per cent), Manitoba (82 per cent), and Saskatchewan (75 per cent), yet even in provinces like British Columbia, where only 34 per cent of households had air conditioning in 2020, this number tripled over the past two decades.

This increasing use of air conditioners means an increased demand for electricity in the summer months. Cooling needs for homes, commercial, and industrial applications are one of the largest energy users. In Ontario, for example, electric utilities report that air conditioning accounts for about one third of the province’s electricity use on the hottest summer days.

The UN has identified cooling as a key sector for action in its Race to Zero Breakthroughs, which are intended to galvanise action ahead of the next global climate meeting, COP26, which is due to take place later this year.

“If we must limit global warming to well below 2oC or by 1.5oC compared to pre-industrial levels, making HVAC solutions less energy intensive is one of the ways we will get there,” says Ayo Daniel Abiola, P.Eng., CEM, a Building and Process HVAC Systems Specialist with Johnson Controls, a global leader for smart, healthy, and sustainable buildings and producer of cooling equipment where he also leads the company’s sustainability efforts in Canada.

The HVAC industry is working on various innovations that will help. For example, Abiola points out that many organizations have developed smart systems to monitor usage patterns, habits, and provide feedback for lowering energy use through predictive maintenance and smart scheduling. HVAC equipment is also now being manufactured to operate at higher efficiency compared to older models, with technologies such as inverters or variable frequency drives that modulate or slow down the fan systems based on room sensors that determine heating and cooling demand.

“Smart, healthy and sustainable cooling solutions are key to accelerating the race to zero and there are many inventions that continue to shape energy-efficient cooling,” Abiola adds, “and I like to add the use of renewable energy such as solar, which can be integrated to power cooling systems and eliminate electricity cost.”

Jeremy Waud, P.Eng., Principal and Manager, Energy Division at H.H. Angus & Associates Limited Consulting Engineers, adds that the industry is seeing an increasing desire on the part of clients to be conscious of their carbon footprint, which impacts the work of not only engineers, but how they work with other professionals as they design buildings. 

“One of the things we’ve been doing is generative design—looking at window-to-wall ratios in buildings and how much soffit overhang there is on a building to see how that relates to the heating and cooling needs of the building,” Waud explains. “We feed that information back to the architect and say, for example, ‘we can reduce our heating and cooling requirements if we make these subtle changes to the building envelope.

“The performance of the building itself, the envelope, the roof, even the positioning of the building on a site, all have impacts on heating and cooling loads. Understanding that going in and trying to optimize things from the outset is important because typically the cost of operating and maintaining a building drastically outweighs the cost of building it, so those lifecycle and energy costs need to be taken into account from day one.”

Staying cool in the summer heat

While building design, HVAC equipment, and smart systems have an impact on efficiently cooling both residential and commercial buildings, Abiola and Waud also offer more immediate suggestions for simpler things that the average person can do at home to stay cool in the summer heat.

If you don’t have air conditioning:

  • Close windows, blinds, or curtains at the right time of day: On hot days, shut your blinds to keep the heat out because your glass windows are one of the easiest paths for heat to get into your home. In the evening, when it is cooler, open the windows to let the colder air from outside enter your home.
  • Strategically plant trees: If you own a home, Abiola suggests planting leafy trees on the south-facing side of your house where the sun is brightest for the longest part of the day. The tree will help shade your house from the heat radiated by the sun.
  • Use a ceiling fan: Ceiling fans use less energy than your air conditioner, and some estimates suggest you could save $20-30 per month on your electricity bill by using a ceiling fan. Turn on the ceiling fan when you are in the room—the downward draft from the fan will allow air to evaporate moisture over your skin thereby cooling you down. Remember to turn off that fan when you leave the room, since it is only effective for lowering your body surface temperature, not the temperature of the room itself.
  • Hydrate: Keep well hydrated with water and eat cold food throughout the day.
  • Take a cool shower: Cool showers, rather than warm, reduce your heating energy bill and help cool down your body’s core temperature.

Even if you have air conditioning, all of the above suggestions will help save you money on your electricity bill, since your air conditioner won’t have to work as hard to cool your home or apartment. If you do have air conditioning, there are also things that you can do to make sure it is operating as efficiently as possible:

  • Move your portable air conditioner to where you are: If you are using a portable air conditioner, Waud suggests moving it to the room where you are spending time so that it is cooling your space, rather than trying to cool multiple rooms or your whole home. If you are working from home, for example, move it to your workspace during the day, and back to your bedroom at night.
  • Maintain your HVAC system: If your air conditioner has maintenance problems, it will have to work harder to cool your home (and the same goes for your furnace in the winter).
  • Replace air filters in your furnace: Waud explains that a clogged or dirty air filter allows less air to flow through it, meaning less cool air circulating through your house and your air conditioner having to work harder to maintain a cool temperature.
  • Dehumidifiers: Humid air gives you a feeling of being warmer than the current temperature. Waud suggests investing in a separate dehumidifier which will take the moisture out of the air in your home and will help the air feel lighter and cooler. 
  • Scheduling: Program your thermostat to allow the temperature in your home to increase while you’re away from home. This reduces the amount of time that compressor in your air conditioner will have to work. However, Waud cautions that you shouldn’t let the temperature creep up too high while you’re out as the air conditioner will have to work harder to cool your home when you return. But an increase of two to three degrees while you are away can result in some energy savings.
  • Smart thermostats: If you can invest in programmable thermostats with sensors that monitor when a room is occupied, Abiola points out that those can also make more efficient use of the air conditioning.
  • Run the fan: If you live in a multi-story house, cool air will naturally settle in the basement, while warmer air gathers at the top of the house. Even if the air conditioning isn’t running, Waud suggests running the fan to circulate that naturally cool air from the basement throughout the rest of the house.

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