Seasonal electricity bill spikes in Ontario (summer and winter)
Seasonal spikes are normal — but they often feel “random” because the bill has multiple moving parts.
Plain-language summary: Temperature drives usage (AC, space heaters, fans), and longer billing periods can amplify the effect.
Your total also includes delivery and other charges that don’t behave like simple “kWh × rate.”
Common summer drivers
- Air conditioning and dehumidifiers
- More time at home (vacation, remote work patterns)
- Higher on-peak usage if AC runs during peak periods (TOU)
Common winter drivers
- Space heaters (they can be huge electricity users)
- More lighting time
- Holiday cooking and gatherings
Why the bill can spike beyond what you expect
- Fixed charges: delivery doesn’t shrink much even if you cut usage a bit.
- Billing days: some months cover more days than others.
- Behavior timing: under TOU, when you use power can matter as much as how much.