ULO vs Time-of-Use in Ontario: Can a Battery Cut Your Hydro Bill?
Ontario's Ultra-Low Overnight (ULO) plan has the cheapest and the most expensive electricity in the province. On its own it is a gamble. With a home battery, it becomes one of the best ways to cut your hydro bill.
TRU Off Grid · October 16, 2026
Ontario's Three Price Plans
Most Ontario homes can choose between three electricity price plans set by the Ontario Energy Board (OEB): Time-of-Use (TOU), Tiered, and Ultra-Low Overnight (ULO). TOU and ULO charge different prices at different times of day. That difference is what a battery takes advantage of.
Current Rates
| Plan | Overnight | Weekday on-peak | Mid-peak | Off-peak / weekends |
|---|---|---|---|---|
| Time-of-Use | 9.1 c/kWh | 18.9 c/kWh | 14.6 c/kWh | 9.1 c/kWh |
| Ultra-Low Overnight | 3.7 c/kWh (11 pm to 7 am) | 37.7 c/kWh (4 pm to 9 pm) | 14.6 c/kWh | 9.1 c/kWh |
OEB prices from November 1, 2026. The OEB sets new prices every November 1, so check your bill for the current numbers.
Why ULO Can Hurt Without a Battery
ULO's overnight price is the cheapest in the province, but its weekday on-peak price, 4 pm to 9 pm, is about double the TOU on-peak price. That is exactly when most families cook dinner, do laundry and run the air conditioning. Without a battery, switching to ULO often costs more, not less.
How a Battery Changes the Math
A home battery charges overnight at 3.7 cents per kWh and then powers your home through the 4 pm to 9 pm on-peak window, so you buy almost nothing at 37.7 cents.
Every kWh moved from on-peak to overnight saves roughly 34 cents on the electricity line, before small charging losses. A home using 10 kWh between 4 pm and 9 pm on weekdays moves roughly 2,500 kWh a year, worth around $800 a year on the electricity charge alone. Add solar and the battery also stores free daytime energy, so savings grow further.
Your result depends on how much power you use and when. We model it from your actual hydro bill, using your local utility's delivery charges, before we recommend anything.
Which Batteries Work Best?
Both systems we install are built for this. EG4 hybrid systems and the Canadian Solar EP Cube 2.0 can be scheduled to charge overnight and discharge on-peak, while keeping a reserve for outages. Bigger batteries cover more of the evening, so on ULO we usually recommend sizing the battery to your full 4 pm to 9 pm usage.
Should You Switch to ULO?
If you have, or are getting, a home battery that can cover your evening usage: usually yes. If you do not have a battery and cannot move your evening usage: usually no, stay on TOU. If you are not sure, send us a recent bill and we will run both plans for you.
Get a Free Savings Estimate
TRU Off Grid designs solar and battery systems around your real usage and current rates, and we file the Home Renovation Savings rebate for qualifying solar and battery systems (up to $10,000). Email your hydro bill to jacob@truoffgrid.com or call Jacob Collier at 647-914-9699.
