Most installers talk about system size in kilowatts, and three sizes come up again and again: 5, 7 and 10 kW. They are convenient round numbers more than magic ones, but each tends to match a recognisable kind of home. All prices here are in Canadian dollars (CAD), before incentives, and are typical planning ranges rather than quotes.
How the numbers are built
Output equals size multiplied by yield. In southern Canada, a kilowatt of panels often produces roughly 1,100 to 1,400 kWh a year, depending on location, tilt, orientation and shading. Cost equals size multiplied by price per watt, and recent installed prices have run about $2.50 to $3.80 per watt, with Atlantic Canada often higher. The price per watt article explains why that spread exists.
| System | Panels (about 420 W) | Yearly output (typical) | Installed cost before incentives |
|---|---|---|---|
| 5 kW | 12 | 5,500 to 7,000 kWh | About $12,500 to $19,000 |
| 7 kW | 17 | 7,700 to 9,800 kWh | About $17,500 to $26,600 |
| 10 kW | 24 | 11,000 to 14,000 kWh | About $25,000 to $38,000 |
Remember that bigger systems often cost a bit less per watt, so the larger sizes may sit toward the lower part of each cost range. A 5 kW Ontario system is often quoted at roughly $14,000 to $18,000, which fits inside the table.
The 5 kW system
Five kilowatts suits a smaller home, a household with efficient appliances, or a roof that simply cannot host more. It covers roughly half to most of the needs of a house using 6,000 to 8,000 kWh a year. It is also the natural choice when you want a modest first step and may add panels later, provided the inverter and utility rules allow expansion. Ask this question at the start, because adding to an existing system is not always simple.
The 7 kW system
Seven kilowatts is a typical family-home size. On a two-storey house with a mix of south, east and west roof faces, 16 or 17 panels fit comfortably. At around 7,700 to 9,800 kWh a year, it can offset most of the use of a household at the lower end of the typical 9,000 to 12,000 kWh range, or a larger share for a home that has trimmed its demand. For many buyers this sits in a sweet spot of cost against savings.
The 10 kW system
Ten kilowatts suits larger homes, electrically heated houses, families planning an electric vehicle, or properties with a heat pump. It needs roughly 40 to 45 square metres of usable roof, depending on panel size, and it may require a bigger electrical service. Check size limits, too. Ontario’s micro-generation threshold was reported to rise from 10 kW to 12 kW on 1 May 2026, and other provinces have caps of their own. Confirm the current rule with your utility before you design.
What decides the right size
Your yearly use
Start with twelve months of bills. If you use 10,000 kWh, a system near 8 kW is the on-paper match, as shown in our guide to how many panels you need.
Your roof
Usable, unshaded area limits the size more often than budget does. A complicated roof can lose a lot of space to vents, chimneys and setbacks.
Export credits
Where exports earn a credit at or near the retail rate and roll over, oversizing slightly can work. Where credits are lower, as in Alberta and Manitoba under net-billing-style arrangements, and Saskatchewan with a below-retail export credit, a system sized to your daytime use may give better value. Details differ by utility and change over time, so verify them.
Future loads
A heat pump, an electric vehicle or an electric water heater can add thousands of kWh. If you plan one within a few years, size for it now or choose equipment that can be expanded.
A note on shading and orientation
The yield range in the table assumes a reasonably clear roof. A system with a west-facing half, or one that loses an hour of afternoon sun to a neighbour’s tree, will land at the lower end or below it. Ask each installer to show the shading analysis behind its production figure. Two quotes for the same size can promise quite different output, and the more modest one is often the more honest one.
Cost per kWh produced
It can help to look past sticker price. Suppose a 7 kW system costs $21,000 and produces about 8,500 kWh a year. Over 25 years that is roughly 212,500 kWh, ignoring degradation, which is about 10 cents per kWh. Degradation of around 0.4 to 0.6 percent a year and an inverter replacement will push that up somewhat. Compare it with your current rate, then use the payback guide to see how long it takes to recover the outlay.
Which size should you ask for?
Rather than choose one, ask installers to quote two sizes, for instance 7 and 9 kW. The difference in price against the difference in expected production shows the marginal return of extra panels. If the extra panels cost a lot per kWh gained, or exceed what your utility will credit, the smaller option is likely better. Our cost overview gives wider context, and the costs and savings hub collects related guides.
Quick answers
How much does a 5 kW solar system cost in Canada?
At recent prices of about $2.50 to $3.80 per watt before incentives, roughly $12,500 to $19,000. A 5 kW Ontario system is often quoted at about $14,000 to $18,000.
How much power does a 10 kW solar system produce?
In southern Canada, often roughly 11,000 to 14,000 kWh a year, depending on location, orientation and shading. Ask for a site-specific estimate.
Is a 7 kW system big enough for a house?
For a household using around 8,000 to 9,000 kWh a year, often yes on paper. Homes with electric heating or an electric vehicle usually need more.
Where to verify
Rules and prices change. Confirm current details with the official bodies below.