Why the 12 month credit clock decides your system size
Alectra pays nothing in cash for surplus generation. What a surplus kilowatt hour earns is a credit applied against future electricity charges, and Ontario's rules set what it is worth: exported power is credited kilowatt hour for kilowatt hour at the retail electricity rate, with no cash payment for net annual excess.
The constraint that actually binds is time. A credit balance carried forward for 12 consecutive unused months is reset to zero at the end of that month. Generation you cannot consume inside a year is generation nobody pays you for, which is why the sensible design target in Vaughan is your own annual consumption rather than the largest array the roof will hold. Having room for more panels is not by itself a reason to install more panels.
So work from twelve months of your own bills rather than from a single summer or winter one. A household with electric heating, an electric vehicle or a heat pump consumes far more, and can justify far more capacity, than an otherwise identical house on gas heat. In a city where roof area is rarely the limiting factor, the consumption profile is the thing worth designing around.
This also changes how you should read a quote. If an installer proposes a system noticeably larger than your annual use, ask what happens to the excess. Under Alectra's rules the answer is that it accumulates as a credit and then expires, so you would be paying for hardware whose output has nowhere useful to go.
What a Vaughan array produces, and when
Vaughan's solar potential is about 1,157 kWh a year for each kW of panel capacity, from Natural Resources Canada's municipal photovoltaic potential dataset. The figure assumes a well oriented, unshaded array, so treat it as a ceiling for your address. Orientation is the biggest single lever: a south-facing plane outperforms an east or west one, and a north-facing plane is generally not worth covering at all.
The year is lopsided. Summer days produce several times what a short, low-angle December day does, and snow sitting on the modules can suppress output for stretches of the winter. Under Alectra's monthly settlement that shows up as a credit balance which builds through the summer and is drawn down through the winter. Judged month by month a well sized system looks alternately excellent and disappointing; judged across a full year it looks like what it is.
Alectra bills residential customers on time-of-use pricing, which means the value of a kilowatt hour you avoid buying depends on the hour you avoid buying it. That raises the value of self-consumption and of storage relative to a flat rate, because timing and not just quantity decides what a kilowatt hour was worth. If a battery is being discussed, it should be modelled against your household's actual load shape rather than added as an upsell.
What Vaughan's housing mix means for your roof
Vaughan's housing stock is dominated by single-detached houses at 62.5% of dwellings, one of the highest shares among GTA municipalities. That is the straightforward case for solar: a private roof you control outright, usually with more than one usable plane, and no attached neighbour whose cooperation you need.
High-rise apartments account for 13.2%, concentrated mainly around the Vaughan Metropolitan Centre area. In a tower the roof belongs to the building owner or the condominium corporation, so an individual resident cannot commission an array there; the question to ask is whether the building owner has any interest in roof access at all. Low-rise apartments under five storeys are a small share here, about 2%, but they fall under the same rule.
Row houses, about 11% of dwellings, typically present a narrower south-facing roof plane, which can limit system size before your consumption does. Semi-detached houses, about 8%, usually still allow an individual install, but the roofline is shared, so work near the party wall needs coordinating with the attached neighbour. In both cases the useful early step is a site visit that measures the usable plane rather than the whole roof.
Applying to Alectra as a Micro Generator
Alectra treats residential solar of 12 kW or less as a Micro Generator connection, and it starts with a preliminary consultation. That is the first point at which the utility looks at your specific address, and it is worth reaching before a full design has been paid for.
From there the order is a Form C connection application, an Offer to Connect with a cost estimate, an Electrical Safety Authority inspected installation and commissioning, and a signed Connection Agreement, after which Alectra installs the bidirectional meter. The system is not meant to run before the agreement is in place and the meter has been changed, so the installation date and the switch-on date are two different dates in your schedule.
The 12 kW threshold is recent. The Ontario Energy Board raised the simplified micro embedded generation threshold from 10 kW to 12 kW as of May 1, 2026, so more residential systems now qualify for the streamlined connection process than did a year ago. A design that comes in just above the threshold buys you a heavier review, which is a reasonable trade only if you know you are making it.
Permits in Vaughan: confirm the requirements with the city
This page deliberately says nothing about Vaughan's building permit requirements, fees or review times, because we could not verify them against the city's own published guidance. Rather than borrow another municipality's rules and hope they transfer, the honest answer is that you should ask the City of Vaughan directly what a rooftop solar installation requires at your address.
What is certain is the electrical side, because that part comes from Alectra rather than from the city: the connection process requires an installation inspected by the Electrical Safety Authority, and a commissioning step, before the Connection Agreement is signed. That inspection is not a substitute for whatever municipal approval the city asks for.
Two questions are worth putting to the city before you sign an installation contract. First, whether a rooftop array on your type of building needs a building permit, and what it costs to file. Second, whether any heritage designation or planning overlay applies to your specific address, since that can change what a visible exterior alteration requires. Then ask your installer, in writing, which of those approvals they file and which ones remain yours.
Programs, and how they interact with net metering
Ontario's Home Renovation Savings Program is the live provincial offer, with combined rebates of up to $10,000 for solar PV paired with battery storage. It launched in January 2025 and runs an expanded 2026-27 programme year from April 1, 2026 to March 31, 2027.
Read its fine print against the sizing question above, because the two interact. Homeowners taking the programme's solar incentive are generally directed to a load-displacement configuration rather than full net metering. Load displacement and net metering treat exported power differently, so a system designed to export surplus under Alectra's credit rules is not necessarily the system the rebate wants to fund. Confirm the current rules with your installer, and with Alectra, before you apply.
On the federal side the Canada Greener Homes Loan, interest free up to $40,000, stopped accepting new applications on October 2, 2025 and is only funding loans already approved. The Canada Greener Homes Affordability Program replaced it in September 2025, delivering no-cost retrofits through participating provinces, which do not currently include Ontario, for low to median income households, with solar PV federally eligible but each province setting its own technology list. There is still no Canadian equivalent of the United States investment tax credit for residential solar.
Beyond those, some municipalities and local utilities periodically run financing programmes such as local improvement charges or on-bill financing. These come and go, so ask what is available in your service area at the time you are buying rather than at the time you start reading.