What a Toronto roof produces in a year
The planning figure for Toronto is 3.7 peak sun hours a day. That is Natural Resources Canada's horizontal plane number: the energy landing on a flat surface, averaged across the whole year. Your panels will not be flat. A south-facing array pitched at a normal roof slope collects more than the horizontal figure does, and a designer models the tilted plane value for your specific pitch and azimuth. So treat 3.7 as the baseline input to a design, not as the number your own array will see.
The annual average also hides how uneven the year is. A Toronto array produces far more in June than in December, and a snow-covered day produces close to nothing. Net metering exists to move that summer output onto winter bills, so no single month tells you anything useful. The only honest way to size a system here is to put a full year of your own bills next to a modelled year of production and compare the totals.
Because of that, roof area is rarely the binding constraint in Toronto. Household consumption is: a system generating well beyond what you use over a year builds up credit you cannot cash out.
How Toronto Hydro credits the power you export
Toronto Hydro runs a Net Metering Program, and you apply through its generation and storage connection process. Exported electricity earns a bill credit calculated the same way your consumption is, and credit above a month's use carries forward for up to 12 months. There is no cheque for net annual excess, so credit you never draw down simply expires at the end of its window.
The detail that should shape your design is which part of the bill that credit touches. It offsets the electricity charge. Delivery and regulatory charges are calculated on Adjusted kWh Used, meaning your gross draw from the grid rather than your net position after exports. So an exported kilowatt hour offsets the commodity portion of your rate and not the all-in rate you pay when you import one back. A kilowatt hour you consume in the house at the moment it is generated avoids every one of those charges at once. Self-consumption is worth more than export in Toronto, and that is what should drive decisions about load shifting and whether a battery earns its place.
The residential customer charge stays on the account either way. Toronto Hydro's Residential Service customer charge is $51.18 per 30 days, effective 1 January 2026, offset slightly by small negative rate riders. No amount of generation removes it, so any payback arithmetic built on the idea of a zero bill is wrong before it starts.
Time-of-Use, Ultra-Low Overnight or Tiered
Toronto Hydro residential customers on the Regulated Price Plan choose between three price structures rather than being assigned one. Time-of-Use prices power by period of the day. Ultra-Low Overnight prices a long overnight window very cheaply and charges more during the weekday on-peak window in exchange. Tiered charges a single price up to a monthly consumption threshold and a higher price above it, whenever you use the power. Toronto Hydro publishes the current prices for all three, and you can switch.
Net metering participants are not shut out of that choice: you can be on any of the three. Which one suits you can change once panels are on the roof, because your bill becomes less about total consumption and more about when you draw from the grid. A household exporting at midday and importing through the evening sits in a very different place on Time-of-Use than on Tiered. If you charge an electric vehicle overnight or run a battery you can schedule, Ultra-Low Overnight changes the arithmetic again.
Which Toronto roof are you working with
Toronto's housing is mostly apartments. Of 1,160,895 occupied private dwellings, 46.7% are in buildings of five or more storeys and another 14.0% are in buildings under five storeys, so 60.7% of the city has no homeowner-controlled roof. If you are in one of those, rooftop solar is not a homeowner permit question at all: it goes to the building owner or the condominium corporation, and it is scoped as a building project rather than a household one.
Ground-oriented housing is the minority here. Single-detached houses are 23.3% of dwellings and usually give an installer a whole roof plane to design around. Semi-detached houses are 6.2% and row houses 5.4%: an individual install is still perfectly possible, but the roof is shared with a party wall and neighbouring units, which affects where equipment can sit and how access and setback space gets drawn. Apartments or flats in a duplex account for another 4.1%, where the answer depends on who owns the structure.
So a rooftop project in Toronto is a question about roughly a third of the housing stock, and the useful first step is working out which third your home is in.
Permits: a 3 business day target, and the ESA sequence
A building permit is required for a roof or wall solar collector larger than 5 square metres, which covers essentially every residential array. The application must include structural calculations stamped by an Ontario registered engineer. Toronto's own solar guidance publishes no snow load or roof capacity number you could check yourself against: the stamped calculation is the test, and it is done against your specific roof, framing and proposed layout.
Toronto Building names solar panel installations attached to an existing building in its Express Services stream, and the published target for that stream is review within 3 business days. It is a target measured on a complete application, not a guarantee: incomplete drawings and missing engineering hold projects up far more often than the city's queue does. Heritage-designated properties are excluded from the stream entirely.
There is no separate City electrical permit for solar in Toronto. Electrical work is reported to the Electrical Safety Authority instead, and the ESA inspection is mandatory. Toronto Hydro will not energize the system until it holds your ESA certificate, so the order of operations is fixed: building permit, installation, ESA certificate, then connection. Ask an installer to walk you through that sequence with dates attached before you sign.
Heritage districts and who controls your roof
Ontario has no US-style homeowners associations, so outside a condominium a detached or semi-detached owner controls their own roof. What Toronto has instead is heritage designation. The city has designated 27 Heritage Conservation Districts under Part V of the Ontario Heritage Act, and every property inside a district boundary is subject to that district's by-law.
Inside a district, altering the exterior needs a heritage permit unless the district plan lists the alteration as minor. For solar the consequence is mainly procedural: Toronto Building excludes any project requiring heritage approval from Express Services, so a heritage property loses the 3 business day review route and goes through a longer process. That is a timeline difference, not a refusal. The practical step is to check whether your address falls inside a district boundary before you plan around the express target.
Incentives, and the either/or you have to settle first
Before applying for anything, know that the two main routes may be mutually exclusive. Toronto Hydro states that customers who take a Home Renovation Savings Program incentive for solar PV and battery storage are not eligible to enter a net metering agreement with it. That is a real choice: an up-front incentive on a solar-plus-battery installation, or a net metering agreement that credits exports for the life of the system. Which one fits depends on how much of your own generation you would consume on site anyway, and it has to be settled before you apply, because the order you apply in can close the other door.
Ontario's Home Renovation Savings Program is the live provincial residential energy program, and it lists combined rebates of up to $10,000 for solar PV paired with battery storage. Program years, caps and eligible measures are revised, so confirm the terms in force on your application date with the program and with Toronto Hydro. Ontario also runs a simplified connection process for small generators and the size threshold has been moving, so ask Toronto Hydro which process your intended system size falls under.
On the federal side, Natural Resources Canada's program page says the Canada Greener Homes Loan is no longer accepting new applications and that only previously approved loans are being funded, with a successor program aimed at low to median income households through participating provinces, which do not currently include Ontario,. Canada has no federal investment tax credit for residential solar comparable to the American one, so do not let a budget depend on finding one.