'How many panels do I need?' is the most common question, and the honest answer is that it is not a number — it is a calculation. The panel count for a BC home comes from your BC Hydro bills, your consumption pattern, your roof and shading, and BC Hydro's self-generation rules. Two homes with the same floor area can need very different systems.
Start with your bills, not your roof area
A solar system offsets consumption. The first input is how many kilowatt-hours you use per month, which you can read from 12 months of BC Hydro bills. Roof area sets the upper limit, but bills set the target — you design to usage, then check whether the roof can host it.
Add your daytime consumption pattern
When you use power matters as much as how much. A home that runs air-conditioning, a heat pump or a home office through the day can offset consumption directly with a grid-tied system. A home where most use is in the evening or winter needs storage to make solar useful — panel count alone does not fix that.
Account for roof, shading, snow and orientation
Orientation (south-facing is best), tilt, shading and snow shedding reduce or increase how much each panel produces. A roof partly shaded in winter, or split across faces with different sun, produces differently from an ideal unshaded south-facing roof. The real production per panel is a site-specific estimate, not a catalogue number.
Understand the BC solar resource
British Columbia has a moderate solar resource. Natural Resources Canada's PV maps give ranges like roughly 1,000 kWh per kWp per year in the Lower Mainland and higher in parts of the Interior. Treat that as background, not a guaranteed site yield — your actual output depends on roof, weather, shading and equipment, and is estimated for your site in the proposal.
What a proper assessment includes
- 12 months of BC Hydro bills and a consumption summary.
- A site and roof survey: orientation, tilt, shading, snow and available area.
- An electrical panel and feeder review.
- A consumption-pattern (daytime vs evening) assessment.
- A production estimate with its method and assumptions stated.