Peak, off-peak, mid-peak: Ontario’s electricity hours explained

For most of us, it’s second nature to fill the dishwasher and run a cycle as soon as the dirty dishes start piling up. But did you know that the same load of dishes could cost you up to 50% more, depending on the time of day you run your dishwasher?

If you live in Ontario and you’re on the Time-of-Use (TOU) pricing system, electricity costs more during high-demand hours (like midday) and less when demand is low (like at night).

There are three TOU price periods: off-peak, mid-peak, and on-peak. In this article, we’ll explain what each one means, how they shift by season and day, and how you can easily remember the cheapest times to use electricity.

What’s the cost difference between on-peak vs. off-peak?

Let’s imagine that you’re running one load of dishes, and your dishwasher is a pretty average 1200-watt model. Modern dishwashers are quite energy-efficient, so a 1-hour load time with a dishwasher like this will only use about 1.2 kilowatt-hours (kWh) of electricity.

Here’s how that same load time translates to cost, given current TOU rates:

In other words, running the same load of dishes during the day vs. at night will cost you roughly double. If you run your dishwasher five times per week, which is average in Ontario, this translates to an extra $25.74 every year — money you could have saved by waiting a few hours!

What are on-peak vs. mid-peak vs. off-peak hours? 

Time-of-Use pricing splits each weekday into three time blocks – each with a different electricity rate: off-peak (cheapest), mid-peak (moderate), and on-peak (most expensive).

Off-peak (least expensive)

When households and businesses use less electricity, typically during the evenings. There is less congestion on the electricity grid, which means electricity is more affordable during this time.

• When: 7 p.m.–7 a.m. on weekdays & all weekends and holidays
• Rate: Cheapest
• Tips: Run major appliances like laundry machines, dishwasher, and EV chargers during this time

Mid-peak (moderate cost)

Mid-peak hours fall between off-peak and on-peak periods, when electricity demand is moderate. These hours change between summer and winter.

• When: Varies by season — either late morning to afternoon or early morning/evening
• Rate: Medium — higher than off-peak but lower than on-peak
• Tips: If you can’t shift your usage to off-peak hours, mid-peak is the next best option. Try to run appliances like ovens or washing machines during this window instead of peak hours.

On-peak (most expensive)

This is when electricity demand is at its highest — typically during weekday mornings and evenings when homes and businesses are using the most power for heating, lighting, and appliances.

• When: Varies by season — typically during morning and early evening
• Rate: Highest — avoid using major appliances during this time
• Tips: Shift routines like cooking, laundry, or charging EVs to off-peak or mid-peak periods. Use timers on smart appliances or programmable thermostats to help automate your energy-saving schedule.

How TOU hours change by season

Because electricity demand shifts in winter and summer, TOU hours for mid-peak and on-peak adjust seasonally. Off-peak hours stay the same all year round.

Summer hours (May 1 – Oct 31)

• On-peak: Weekdays 11 a.m.–5 p.m.
• Mid-peak: Weekdays 7–11 a.m. and 5–7 p.m.
• Off-peak: Weekdays 7 p.m.–7 a.m., plus all weekends and holidays

Winter hours (Nov 1 – Apr 30)

• On-peak: Weekdays 7–11 a.m. and 5–7 p.m.
• Mid-peak: Weekdays 11 a.m.–5 p.m.
• Off-peak: Weekdays 7 p.m.–7 a.m., plus all weekends and holidays

Weekends and holidays are always off-peak

Weekends and holidays are always the cheapest time to use electricity. Why? Offices and commercial buildings – major energy users – are mostly closed, easing strain on the grid and lowering costs.

This is why it’s best to save your laundry and other energy-heavy tasks for the weekend.

Here are the statutory holidays in Ontario that count as off-peak:

• New Year’s Day
• Family Day
• Good Friday
• Victoria Day
• Canada Day
• Civic Holiday
• Labour Day
• Thanksgiving Day
• Christmas Day
• Boxing Day

If a holiday falls on a weekend, off-peak rates apply on the following weekday. For example, if New Year’s Day lands on a Saturday, you’ll still get off-peak rates on Monday.

You can always check the Ontario Energy Board website for the most up-to-date holiday schedule.

Easy ways to remember and use TOU hours

Here’s a simple rule to keep TOU hours top of mind:

Evenings, weekends, and holidays = cheapest electricity

• Group your “high energy” chores and do them in batches after 7 p.m. or on weekends.
• Use smart appliances and programmable thermostats to run automatically during off-peak hours.
• Set phone reminders or recurring calendar alerts to start tasks at cheaper times.
• Start appliances before bed — most run quietly, and you’ll wake up to clean dishes or dry clothes.
• Post a TOU cheat sheet on your fridge so the whole household is in the loop.

Gain a clearer understanding of your energy habits

Many people try to save energy by upgrading to efficient appliances, using smart tech, or shifting to off-peak hours. But without clear feedback, it’s hard to know what’s actually working. Most energy data is buried in hard-to-read graphs or scattered across bills and dashboards.

Jotson makes it easy to view your electricity and natural gas usage over time by securely importing your utility data through Ontario’s Green Button program. You can clearly see the impact of your habits, spot what’s driving up your bill, and take action.

Download the Jotson app for free and take the guesswork out of saving energy.