The demand for electricity is way up this summer due to the extreme heat and that could mean consumers' monthly power bills will go up, according to Toronto Hydro.

Although sweltering summer days are nothing new to Toronto, the city-owned utility says the number of days over 30 C has spiked this year compared to last, and that means more electricity is being used to power air conditioners.

"Last year was a really cold summer — we basically didn't have a summer in Toronto, Toronto Hydro spokesperson Tori Gass said.

All of last summer, the utility says, the 4,000 megawatt mark was passed five times. But just a month into this year's summer season, that same mark has been exceeded seven times.

"People might be remembering what their bills were last summer, but this year is going to be a lot different," Gass warned.

Customers often don't understand just how much running their air conditioners is costing them, she said.

Toronto Hydro spokesperson Tori Gass says increased electricity usage in the city is directly to the extreme heat this summer. (Gary Asselstine/CBC)

"People may not realize, but it can account for up to 50 per cent of your summer bill," said Gass.

According to Gass, your monthly bill may depend on the age of your air conditioner, as well. She says if you've got an older one, chances are it's less efficient.

She suggests consumers set their air conditioners to 25 C during the day, and lower it to 22 C during off-peak hours. She predicts the strategy could save consumers up to $20 per month.

Impacts of extreme heat on the power grid

Terry Young, vice president of the Independent Electricity System Operator (IESO) — the crown corporation responsible for operating Ontario's energy market — says there's no denying that the heat has taken a toll on Ontario's power grid.

"A week ago, we set a record in terms of demand for electricity for the year — it was around 23,000 megawatts. We haven't seen peaks like that for years," said Young.

As electricity usage continues to rise, there have been concerns about whether or not Toronto's power grid can sustain the demand without the power outages and blackouts the city has suffered in the past.

But since the massive blackout that engulfed northeastern North America back in 2003, improvements have been made with these spikes in usage in mind, according to Young.

"We're in a situation where we have an adequate amount of electricity to meet those high demands," he said.

Gass calls the fight against extreme weather a "balancing act", and says "when it starts to get really hot outside for several days in a row, there can be a strain on the equipment."

Young agrees, but says he's confident the utility has the protocols in place to remain fully operational.

"We're in a business where we never say never, but at this point in time, our ability to meet these high demands leaves us in good shape," he said.