Capacity and production are different
A proposed array might be described by its rated capacity in kW. That is not the same as the energy it produces over a year in kWh. Production changes every hour with sunlight, temperature, orientation, shade, snow and equipment losses. Compare annual kWh estimates rather than assuming that a larger panel number always means the same household benefit.
A useful proposal gives monthly estimates and an explanation of its modelling assumptions. Natural Resources Canada’s photovoltaic potential maps can provide regional context, but an on site shade and roof assessment is still needed. A north facing obstruction or a neighbour’s tree will not appear in a generic marketing average.
Follow electricity through the house
When solar produces while appliances are running, some production can be used in the home immediately. If production exceeds demand, the excess may flow to the grid under an approved net metering arrangement. At night or when demand exceeds production, the home draws from the grid unless a battery is providing power.
This is why a solar generation chart and a utility bill are not the same thing. The bill records electricity crossing the utility meter and applicable charges; the inverter records what the array produced. To understand true household use, look at those flows together.
What Ontario net metering does
Under Ontario’s current program, eligible renewable electricity exported to the grid can create a bill credit calculated by the distributor. Credits may carry forward for up to 12 months. The program is a credit mechanism, not a simple promise of a cash payment for every kWh. Fixed and other bill charges may still remain.
The current rules and the distributor’s agreement determine the details. The province says to apply for connection before purchasing or installing equipment. Ask the distributor how credits appear on your actual rate plan and whether there are local connection constraints.
Why a payback claim needs careful inputs
A useful financial comparison includes installed cost, roof work, financing, maintenance, equipment replacement, electricity rate assumptions and the value of exported energy. It should show more than one scenario. A salesperson’s single “savings per month” number can hide an aggressive production estimate or ignore charges that solar does not eliminate.
Look at the household’s measured use first. If usage changes because of an electric vehicle, heat pump or efficiency upgrade, an old bill may be the wrong sizing basis. Consider what the system does for resilience separately from what it does for the bill; ordinary grid tied solar alone generally does not keep a house powered during an outage.
Plan for ownership after commissioning
Ask who has access to production data, whether the owner can export it, and how alarms are delivered if an inverter stops producing. Keep a copy of drawings, serial numbers, warranty terms, permits and the distributor approval. The system should be understandable without needing the original salesperson to explain every screen.
Review actual production after the first full year against the weather and the proposal’s assumptions. That is a better way to judge performance than comparing one cloudy week to a perfect test day.
CHECK THE SOURCE
Official reading
Programs, equipment and requirements can change. These sources provide current technical and Ontario program details to check before a project.
This is a planning guide, not an installation procedure or a savings guarantee. Have the roof, electrical service, distributor connection and battery design assessed for the actual property. Reviewed 12 October 2026.
