Generation and shading
How much electricity could solar panels generate on my home?
Solar generation is usually estimated in kilowatt-hours per year. A useful estimate combines the proposed system’s capacity with the roof’s location, direction, incline, shading and modelling assumptions.
By VERA · Reviewed
Keep power and energy separate
Kilowatts describe power at a moment in time; kilowatt-hours describe energy over a period. A system rated at a certain number of kilowatts does not produce that power all day. Daylight and operating conditions vary, so the annual energy figure answers a different question from the equipment rating.
Check what the estimate includes
Ask which roof faces and panels are included, how shading is handled and whether the figure accounts for system losses. Different assumptions can change the result even when two quotations show the same nominal panel capacity.
Use annual estimates appropriately
An annual estimate is a planning tool, not a promise for every year or every day. It also does not say how much electricity the household will use directly. VERA’s assessment helps you understand your proposed roof layout and generation as part of getting your free solar quote.
Sources and further reading
This guide gives general information. Your assessment is an estimate; installation design, suitability and price need confirmation for your property.
Keep exploring
- How do trees and nearby buildings affect solar panels?
- Do solar panels work in winter and cloudy weather?
- How do east–west solar arrays compare with south-facing panels?