Quick answer: Less than the marketing suggests. Most Australian roofs capture the large majority of the ideal yield. Enter your direction, tilt and postcode into the free calculator below to get your exact percentage.
Solar marketing loves the idea of the perfect angle. Panels facing due north, tilted at exactly your latitude, drinking in every available photon. It sounds like anything less is leaving money on the table.
The truth is more reassuring. Real roofs get surprisingly close to ideal, and the gap is usually smaller than a single shaded panel or an unnoticed fault would cost you.
What does “percent of ideal yield” mean?
Imagine the best possible array at your location: perfect direction, perfect tilt. Call its annual output 100%. Every real roof captures some share of that, and the share depends on just three things: which way the roof faces, how steep it is, and where in the world it sits.
A north facing roof at a typical Australian pitch lands close to the top. Tilt it a bit flatter or swing it toward north east or north west and you give up a little. Even a full east or west facing roof at normal pitch still captures a healthy share, which is why installers happily fill east and west faces once north is used up.
How do I get my number?
Our free Solar Panel Angle Calculator takes your roof direction, tilt and postcode and shows you the percentage of ideal yield your roof captures. If you don’t know the direction or tilt, the Roof Azimuth Calculator and Roof Tilt Calculator will measure both in a couple of minutes, straight from your browser.
Armed with that number, you can judge quotes properly. If an installer says your roof is “no good for solar”, you can check whether that’s true or just a rushed assessment.
The angle is fixed. The output isn’t.
Whatever your roof captures, that’s the ceiling. The floor is set by faults, shading and slow degradation, and those you can do something about. PV Fleet learns what your system should produce and alerts you within hours when it drops below that, on any inverter brand, with no new hardware. Book a free demo if you’d like to see it on a live system.