Calculator
How many solar panels do I need?
Enter your bill or yearly kWh to estimate system size, panel count, roof space and typical installed price for your province. It takes ten seconds.
You’d need about
9.0 kW
21 panels of 430 W, making about 9,807 kWh a year of the 9,635 kWh you use.
- Roof space
- 41 m²
- about 441 sq ft of usable roof
- Typical installed price
- $21,853–$27,542
- before rebates, at $2.42–$3.05/W
Based on 1,086 kWh a year per kW in Ontario (our model, a well-placed roof). Shade, a steep north face or a small roof all change this, so the real answer depends on your roof.
How the calculation works
We convert your bill into kWh using your utility’s actual prices, multiply by how much of that you want to cover, and divide by the yearly output of one kW of panels in your province from our model. Then we round up to whole panels.
It assumes a well-placed roof. Your real roof might face east or west, have shade or have less space. Check your roof to size it on the actual faces, or read how many solar panels you need.
- How many solar panels does an average Canadian home need?
- A home using about 9,000 to 10,000 kWh a year typically needs a 7 to 11 kW system, or roughly 17 to 26 panels of 430 W, depending on the province and the roof.
- How is solar system size calculated?
- Divide the electricity you want to cover in a year by what one kW of panels makes where you live. For example, 9,600 kWh ÷ 1,086 kWh per kW is about 8.8 kW in Toronto.
- Should I cover 100% of my usage?
- Where net metering credits exports one for one, covering about 100% is common. Where exports earn little or nothing, a smaller system that matches daytime use usually pays back faster.
- How much roof space do I need?
- Each 430 W panel takes about 2 m² (21 sq ft). Fire setbacks, vents and shade reduce the usable area, so most roofs fit fewer panels than their size suggests.