Extreme heat

Heat can harm by pushing the human body beyond its limits. Under normal conditions, the body's internal thermostat produces perspiration that evaporates and cools the body. In extreme heat and high humidity, evaporation is slowed and the body must work harder to maintain a normal core temperature.

Extreme heat or heat waves can be particularly dangerous for children, the elderly, and people who are ill or overweight. A heat wave is defined as three or more days of temperatures of 32°C or more.

In Ontario, during the summer months, there is the added threat of poor air quality when extreme heat combines with air pollutants from industry, gas-powered vehicles and other sources.

What you can do during an extreme heat emergency

·         Stay indoors as much as possible. If air conditioning is not available, stay on the lowest floor, out of the sun.

·         Eat well-balanced, light and regular meals.

·         Drink plenty of water, even if you do not feel thirsty.

·         Limit your intake of alcohol and caffeine.

·         Dress in loose-fitting clothes that cover as much skin as possible.

·         If your home is not air-conditioned, consider spending the warmest part of the day in air-conditioned public buildings, such as libraries, movie theatres, shopping malls, and other community facilities.

·         Check on family, friends and neighbours who do not have air conditioning and who spend much of their time alone.

Preparing your home for a heat wave

·         Install window air conditioners snugly; insulate if necessary.

·         Close any flood heat registers nearby and use a circulating or box fan to spread cool air.

·         Check air conditioning ducts for proper insulation.

·         Install temporary reflectors on windows, such as aluminium-covered cardboard, to reflect heat back outside. Weather-strip doors and windows to keep cool air inside.

·         Cover windows that receive morning or afternoon sun with drapes, shades, awnings or louvers to reduce the heat that enters your home.

Power supply emergency

During periods of extreme heat and humidity, the demand on our power grid can increase significantly. The increased demand could potentially exceed the supply of electricity available, thus creating the risk of rotating blackouts or large-scale power outages. The Independent Electricity System Operator (IESO) may issue a conservation appeal to decrease the risk to our power grid.

You can do your part in helping to prevent a potential power supply emergency by implementing these conservation measures during times of high heat and humidity:

·         Turn off your air conditioner when you are not at home.

·         Use a programmable thermostat to adjust the temperature of your home.

·         Set your central air conditioning to a higher temperature during conservation appeals.

·         Use ceiling fans. Use fans instead of air conditioners in, or next to, an open window so that heat can be exhausted to the outside.

·         Close blinds and curtains during the day to help keep heat out.

·         Replace incandescent lighting with fluorescent lights.

·         Computers, stereos, and televisions use power even when they're turned off. Plug them into a power bar and turn off the power bar.

·         Keep lights off as much as possible.

·         Cook outdoors rather than using the stove.

·         Shower and run the dishwasher, washer and dryer before 8 a.m. and after 8 p.m.

·         Dry wet clothes outdoors.

·         Keep refrigerator and freezer doors closed as much as possible.

·         Turn off pool heaters. Vacuum pools once a week, rather than daily.