Net Metering in Ontario Explained: How Your Solar Panels Actually Pay You Back

Net metering is the billing arrangement that makes rooftop solar economically workable in Ontario, and it is also the part of going solar that homeowners misunderstand most often. It is not a cash payment, and it is not a feed-in tariff that pays you a premium for every kilowatt-hour you generate. It is a credit: when your panels produce more than your house is using in a given moment, the surplus flows out to the grid and your meter records a credit at the same per-kilowatt-hour value you would pay to draw power back. Over the year, exports and imports are netted against each other.

The key distinction is that you are compensated for exported energy, not for total generation. A panel that powers your own air conditioner at noon does not earn you anything — it just spares you from buying that power. Only the surplus that leaves your property becomes a credit. This is why self-consumption and system sizing interact so strongly with your actual bill.

To see how the math plays out, picture a fairly typical Ontario home: about 9,000 to 10,000 kWh of annual electricity use, a south-facing unshaded roof, and a 7 kW array that produces roughly 8,500 kWh over the year. That array is deliberately a touch smaller than the household's annual consumption, and that is the point. In the long days of June and July the panels will comfortably exceed what the house draws during daylight — especially if the occupants are out — and the surplus exports build a credit balance. Through the dark months of December and January, when a heat pump or resistance heat is running and production is at its annual low, the house imports more than it exports and the credit gets drawn back down.

The settlement is not monthly. Most Ontario net metering accounts settle on an annual true-up cycle, which means the running credit carries forward month to month and is reconciled once a year, typically on the anniversary of the connection. So the summer surplus is banked, not cashed out, and it is there to absorb the winter drawdown. If, at true-up, you have imported more than you exported over the year, you pay for the net difference at your normal retail rate. If you exported more than you imported, the surplus credit is generally not paid out in cash — it may roll forward or be settled at a much lower value, depending on your utility's rules, which is exactly why oversizing does not pay.

That annual cycle is the heart of why sizing matters more than panel count. A system that looks generously balanced in July — when the roof is bathed in light and the house needs little — can still leave you importing through January. The relevant target is annual consumption, not peak summer production. Match the array's expected annual kilowatt-hours to your household's annual kilowatt-hours, and the true-up will land close to zero, which is the economically ideal outcome: you have used your own generation and banked the surplus for the season you need it, without paying for a larger array than the year can absorb.

Oversizing is the most common and most expensive mistake. Homeowners see a large unshaded roof and assume more panels means more savings, but Ontario net metering does not reward uncompensated surplus. A 10 kW array on a 9,000 kWh household will produce a fat summer credit that, at true-up, either rolls forward indefinitely or settles at a fraction of its retail value — money spent on panels that never returns as bill savings. The extra capacity also does nothing for your winter deficit, because winter production is limited by short days and low sun angle, not by array size beyond a point.

Undersizing out of caution is the opposite error and it is subtler. A 4 kW array on the same 9,000 kWh home will run a summer surplus too small to carry the winter, so you pay for grid power through the dark months with little credit to offset it. The bill never approaches zero and the payback stretches out. The fix is not to guess; it is to size against your actual annual usage from a year of utility bills, with a realistic derate for orientation, shading, and inverter losses.

Two more mistakes round out the common set. First, ignoring seasonal production swings leads people to plan around a single month's bill rather than the full year, and net metering is an annual mechanism — a great July tells you almost nothing about your true-up. Second, confusing net metering with time-of-use rate arbitrage. Time-of-use is about when you draw power; net metering is about the net of what you export versus import over the year. Shifting your laundry to off-peak hours is a fine habit, but it does not change the fundamental annual balance your array has to hit.

It is also worth being clear about what net metering is not. It is not the old microFIT program, which paid a set rate per kilowatt-hour generated and exported. Net metering gives no premium and no guaranteed rate; it gives a credit valued at what you would otherwise pay. That makes it more transparent and tied to your own usage, but it also means the economics are entirely in your sizing and your consumption profile, not in a feed-in tariff floor.

Your local utility's specific rules matter too. Most Ontario utilities offer net metering and follow broadly the same annual true-up structure, but the details — how surplus is handled at true-up, whether there are minimum charges, how bi-directional metering is configured — vary. Confirm your own utility's net metering terms before sizing an array, because the same physical system can produce different annual outcomes ten kilometres apart.

Where this leaves you is that the single most valuable step before buying panels is a proper sizing assessment based on your actual annual consumption and your specific roof. Production estimates are only as good as the assumptions behind them, and a quote that leads with panel count rather than annual kilowatt-hours is a warning sign. The goal is not the biggest array you can fit; it is the array that brings your annual true-up closest to zero against the way your household actually uses power.

If you're weighing system size against your actual annual usage, Solify's residential incentives guide is a useful starting point for a proper sizing assessment.

Finally, remember that net metering works best on a home that has already addressed its biggest loads. A heat pump on a leaky, under-insulated envelope will pull far more winter power than a well-sealed one, and that shifts the sizing target upward for the same comfort. The sequence — envelope first, then heat pump, then right-sized solar matched to the resulting annual use — is what makes the annual true-up actually come out close to zero. Get the sizing right and the panels quietly do their job across the year; get it wrong and you will be reading your true-up statement every spring wondering where the savings went.