Ontario TOU vs ULO vs Tiered for solar homes

Ontario households on the Regulated Price Plan can choose between three ways of paying for electricity: Time-of-Use (TOU), Ultra-Low Overnight (ULO) and Tiered. The best choice depends on when you use power, and adding solar or a battery can change which plan suits you.

The prices below are set by the Ontario Energy Board and take effect November 1, 2026. They cover the electricity itself, not delivery or regulatory charges.

The three plans at a glance

The TOU periods shown are the winter schedule. The Ontario Electricity Rebate of 15.7% is applied to eligible bills.

How each plan works

Time-of-Use

TOU is the default for most homes. Prices step up during weekday mornings and evenings. The gap between the cheapest and most expensive hours is moderate, about 2 times.

Ultra-Low Overnight

ULO has a very cheap overnight rate and a very expensive weekday 4 to 9 pm window. The on-peak price is about 10 times the overnight price. It rewards households that can shift use to overnight, such as by charging an electric vehicle or running a dishwasher late.

Tiered

Tiered charges a flat price no matter the time of day, with a higher price once monthly use passes a threshold. It suits households that use a lot of power during weekday peaks and can't shift it.

How solar fits each plan

Solar panels produce most of their energy around midday, roughly 10 am to 3 pm, and much less in the late afternoon.

• On TOU, midday production lines up with the weekday mid-peak period at 14.6 cents, so every kWh you use directly saves a mid-range price.
• On ULO, midday production falls mostly in the mid-peak period at 14.6 cents. Panels do little to cover the expensive 4 to 9 pm window, especially in winter when the sun sets early.
• On Tiered, every kWh of solar saves the same price, and solar can keep more of your use in the lower tier.

With net metering, how your exported power is credited also interacts with your rate plan. SolarMyBill models this for you rather than relying on a single average price.

How batteries change the picture

A battery is most valuable on ULO. It can charge from cheap overnight power or surplus midday solar, then run the home from 4 to 9 pm on weekdays. That gap, from 3.7 cents to 37.7 cents, is the largest price spread available to Ontario households.

On TOU, the gap is smaller, so a battery saves less per kWh shifted. On Tiered, there is no time-based gap at all, so a battery offers backup but little bill savings. Our battery guide works through an example.

Which plan should a solar home choose

There is no universal answer, but some patterns hold:

• Solar plus battery: ULO is often the strongest fit, if the battery is sized to cover most 4 to 9 pm weekday use.
• Solar only, home during the day: TOU or Tiered is often safer than ULO, because the 37.7 cent evening window is hard to avoid without storage.
• Electric vehicle owners: ULO can be attractive if you charge overnight, with or without solar.

You can switch plans by contacting your local utility. Check how often switching is allowed before you decide.

What SolarMyBill does

We estimate your bill on all three plans, before and after solar, and with and without a battery. That way you see the plan that fits your home after the change, not just today.

Next step

Compare plans for your own usage: check your roof.

Sources

• Ontario Energy Board: electricity price changes effective November 1, 2026