The four numbers on your Ontario hydro bill that decide whether solar is worth it
Your Ontario hydro bill holds four pieces of information that decide whether solar makes financial sense for your home: your annual kilowatt hour use, your price plan, the split between electricity charges and everything else, and your local utility. Everything else on the page is detail. This guide shows you where each one sits.
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Which four numbers actually matter?
Most people look at the total, wince, and file the bill away. For estimating solar, the total is close to the least useful number on the page.
Here is what to pull instead.
| What to find | Why it matters | Where it usually sits |
|---|---|---|
| Annual use in kilowatt hours (kWh) | Sets the system size you need. This is the single biggest input | Usage graph, or your utility's online account |
| Your price plan (TOU, Tiered, or ULO) | Decides what each saved kilowatt hour is worth | Electricity section, near the rates |
| Electricity charges versus all other charges | Only part of your bill is reducible by solar | Charge breakdown |
| Your local utility | Delivery rates, connection process, and timelines differ by utility | Top of the bill, with the account number |
Write those four down before you touch any calculator, including ours. Estimates built on a guessed usage figure are close to worthless.
Where do you find your annual kilowatt hour use?
This is the number people get wrong, because a single bill only shows one month, and one month is not representative. A February bill in an electrically heated home and a May bill in the same home can differ by hundreds of kilowatt hours.
Three ways to get the full year:
The usage graph on the bill. Most Ontario utilities print a bar chart showing 12 or 13 months of consumption. Add the bars. It is tedious but it works.
Your utility's online account. Nearly every Ontario utility offers billing history you can view or export. This is faster and more accurate than reading a chart.
Green Button. Ontario has a standard called Green Button that lets you download your own detailed usage data, or authorise sharing it with an app or service. The Ontario Energy Board maintains a plain explanation of how Green Button works. If your utility supports it, this gives the cleanest data by a wide margin.
One caution. If anything about your household changed in the past year, a new electric vehicle, a heat pump, a hot tub, a new baby, a home office, last year's usage understates next year's. Adjust upward or your system will be undersized.
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How do you tell which price plan you are on?
Ontario households on the Regulated Price Plan choose between three structures. Your bill names the one you are on in the electricity section.
The Ontario Energy Board sets these prices once a year, effective November 1. The prices below took effect November 1, 2025 and run to October 31, 2026, according to the Ontario Energy Board.
Time of Use (TOU) prices, effective November 1, 2025
| Period | Summer hours (May 1 to October 31) | Price (¢/kWh) |
|---|---|---|
| Off peak | Weekdays 7 PM to 7 AM, weekends and holidays all day | 9.8 |
| Mid peak | Weekdays 7 AM to 11 AM and 5 PM to 7 PM | 15.7 |
| On peak | Weekdays 11 AM to 5 PM | 20.3 |
Source: Ontario Energy Board, prices effective November 1, 2025. Winter periods (November 1 to April 30) swap the mid peak and on peak hours.
Ultra-Low Overnight (ULO) prices, effective November 1, 2025
| Period | Hours (same all year) | Price (¢/kWh) |
|---|---|---|
| Ultra-low overnight | Every day 11 PM to 7 AM | 3.9 |
| Weekend off peak | Weekends and holidays 7 AM to 11 PM | 9.8 |
| Mid peak | Weekdays 7 AM to 4 PM and 9 PM to 11 PM | 15.7 |
| On peak | Weekdays 4 PM to 9 PM | 39.1 |
Source: Ontario Energy Board, prices effective November 1, 2025.
The ULO spread of 3.9 cents against 39.1 cents is the number every battery quote points at, but the arbitrage math is not as generous as it looks once you account for what a battery can and cannot shift. Our Ontario ULO arbitrage guide walks through the five reasons most solar quotes overstate this figure.
Tiered prices, effective November 1, 2025
| Tier | Residential threshold | Price (¢/kWh) |
|---|---|---|
| Tier 1 | First 600 kWh per month in summer, first 1,000 kWh in winter | 12.0 |
| Tier 2 | Everything above the threshold | 14.2 |
Source: Ontario Energy Board, prices effective November 1, 2025.
Why this matters for solar: the ULO plan carries the widest gap between its cheapest and most expensive periods, 3.9 cents overnight against 39.1 cents on weekday evenings. That gap is what makes battery storage worth modelling. On a Tiered plan, where every kilowatt hour costs close to the same, storage has far less to work with. Our Canadian electricity rates comparison sets Ontario against the other provinces.
Why does your bill total not match your rate times your usage?
Because four other things happen between the rate and the total.
Delivery. The cost of moving electricity from the generator to your meter. It has a fixed monthly portion that does not change no matter how little you use, plus a variable portion tied to consumption. The amounts differ by utility, which is why two Ontario households using identical electricity can pay different delivery charges.
Regulatory charges. The cost of administering the provincial grid and market. Small, but it is there.
The Global Adjustment. This covers the gap between what generators are guaranteed and what they earn in the wholesale market, plus some conservation programs. If you are on a Regulated Price Plan, the Ontario Energy Board confirms it is already baked into the TOU, ULO and Tiered prices above rather than shown separately. It only appears as its own line if you are on a contract with an energy retailer.
The Ontario Electricity Rebate (OER). A provincial credit applied to your bill. The Ontario Energy Board announced that the OER changed to 23.5 per cent effective November 1, 2025, and estimated it reduces a typical residential bill by roughly $36 a month for a household using 700 kWh.
Then HST is applied. The result is that your effective cost per kilowatt hour, meaning your total bill divided by your kilowatt hours, is usually meaningfully higher than the headline rate on your price plan. That effective figure is the honest one to use when you are judging solar.
Which charges can solar reduce, and which never go away?
This is the part most people misunderstand, and it is the difference between a realistic expectation and a disappointed homeowner two years later.
| Bill component | What solar does to it |
|---|---|
| Electricity charges | Reduced. This is where solar savings come from |
| Variable delivery | Reduced only where it is billed per kilowatt hour |
| Fixed monthly delivery | Unchanged. You pay it while you stay connected to the grid |
| Regulatory charges | Largely unchanged |
| Ontario Electricity Rebate | Shrinks alongside the charges it applies to |
| HST | Falls only as the charges beneath it fall |
The plain version: solar reduces what you buy, not what you pay to stay connected. A grid connected home in Ontario keeps a monthly bill even in a month where the system produces everything the household uses. Anyone telling you your bill goes to zero is selling, not explaining.
There is a second decision layered on top. Ontario homeowners generally have to choose between the Home Renovation Savings rebate path and traditional net metering, because a rebated system is configured for on site consumption rather than grid export. The two are not stackable, and picking the wrong one costs real money. We break the choice down on our Ontario solar page. Program terms change, so confirm the current rules with Save on Energy before you sign anything.
What your bill will not tell you
Your bill is the demand side of the equation. It says nothing about the supply side.
Roof orientation, pitch, shading, roof age, available unshaded area, and your electrical panel capacity all change what a system produces and what it costs to install. A south facing roof and an east facing roof with identical bills need different system sizes and different budgets.
So treat any estimate, including the one our tool produces, as a starting range built on stated assumptions rather than a quote. Installed pricing in Canada varies by province, system size, and site conditions, which we cover in our solar panel cost breakdown. Only a site assessment by a licensed installer produces a real number, and no permit, rebate, connection approval, or install date is guaranteed until the approvals are actually complete.
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Frequently Asked Questions
Common questions readers ask about this topic
Most Ontario bills print a 12 or 13 month usage graph you can add up. Faster options are your utility's online billing history, or Green Button, an Ontario standard that lets you download your own detailed consumption data. Use a full year, because a single month is not representative of annual use.
The Ontario Electricity Rebate is a provincial credit applied to eligible residential, small business and farm electricity bills. The Ontario Energy Board announced it changed to 23.5 per cent effective November 1, 2025, and estimated it lowers a typical residential bill by about $36 a month for a household using 700 kWh.
Solar reduces the electricity you buy, not the cost of staying connected to the grid. Fixed monthly delivery charges and most regulatory charges continue regardless of how much your system produces. A grid connected Ontario home keeps a monthly bill even in high production months.
It depends on your usage pattern, not on a single best answer. The Ultra-Low Overnight plan has the widest spread between its cheapest and most expensive periods, 3.9 cents against 39.1 cents per kilowatt hour as of November 1, 2025, which gives battery storage the most to work with. Tiered pricing has a much narrower spread.
Not for most households. If you buy electricity through the Regulated Price Plan, the Ontario Energy Board confirms the Global Adjustment is already included in the Time of Use, Ultra-Low Overnight and Tiered prices. It appears as its own line only for customers on a contract with an energy retailer.
It gives you a realistic range for system size and annual production, not a quote. Your bill describes what you consume. It says nothing about roof orientation, shading, roof age, or electrical panel capacity, all of which change cost and output. Installer quotes govern the real number.
Editorial note: Regulated Price Plan rates are set by the Ontario Energy Board and reset each November 1. The figures on this page are effective November 1, 2025 through October 31, 2026. Confirm current rates with your utility and with the Ontario Energy Board before making a purchase decision. Program terms for the Home Renovation Savings rebate change, so confirm with Save on Energy before signing.
Sources
- Ontario Energy Board, Electricity rates.
- Ontario Energy Board, Understanding your electricity bill.
- Ontario Energy Board, Green Button.
- Ontario Energy Board, Ontario Energy Board Announces Changes to Electricity Prices for Households, Small Businesses and Farms, October 17, 2025.