Panel groups — column reference

Name

A free-form label for this group of panels — e.g. “North roof”, “Garage west”, “Carport”. Names appear in the chart legend so you can tell at a glance which group is producing what through the day.

The name is for your benefit only — the simulator doesn’t use it to derive any physics. Keep it short and meaningful (the legend cuts off long labels).

Azimuth (°)

The compass direction the panels face, in degrees from true north, measured clockwise:

• 0° — due north (best in the southern hemisphere; AU/NZ/ZA)
• 90° — due east (morning sun)
• 180° — due south
• 270° — due west (afternoon sun)

The hemisphere matters: in the southern hemisphere (Australia, NZ, southern Africa) the sun tracks across the northern sky most of the year, so a north-facing roof collects the most annual energy. In the northern hemisphere (UK, Ireland, USA, Canada, Europe) it’s the opposite — due south is best. East-facing panels make their power earlier (good if you have a morning load peak); west-facing panels match late-afternoon air-con use and hit peak-priced grid windows on hot days. Mixing orientations smooths your production curve.

Use a compass app on your phone, or read the azimuth off a satellite view of your roof in Google Maps.

Tilt (°)

The angle of the panel from horizontal. A flat panel is 0°; a vertical wall-mount is 90°. Typical residential roofs sit between 15° and 35°, varying by country and builder convention.

Rule of thumb for annual yield: tilt close to your local latitude is optimal. At common reference latitudes that works out to roughly ~28° (Brisbane, Houston), ~33° (Sydney, San Diego, Cape Town), ~38° (Melbourne, San Francisco, Madrid), ~52° (London, Berlin), ~52° (Calgary). In practice your roof tilt is whatever the builder gave you; just enter that. A few degrees off optimum loses very little (often less than 5 % annual).

For ground-mount or carport installs you can set the tilt deliberately. Steeper tilts (40°+) favour winter production and shed dust + leaves better; shallower tilts (20°–25°) favour summer production and total annual energy.

Power (W)

The rated peak DC power of one panel in this group, in watts. This is the number printed on the panel’s spec sheet next to “STC Pmax” — e.g. 440 for a typical 2024-era residential panel, 370 for a 2018 install,250 for a 2012 install.

The simulator multiplies this by the count and the system efficiency (default 0.85, which captures DC wiring losses, inverter efficiency, soiling, and panel temperature derate at typical sunny-summer roof temperatures) to derive the AC power output.

If a group has mixed-power panels (rare, usually a sign of a partial replacement), enter the average and use the count of the full string.

Count

The number of panels in this group. All panels in one group are assumed identical (same azimuth, tilt, power) — if half your north-facing panels are 440 W and half are 370 W, split them into two groups.

Total system size is just the sum of (count × power) across all groups, divided by 1000 to get kW. A typical residential install runs 6–13 kW (roughly 15–30 panels at 440 W each); off-grid, rural, and EV-heavy installs go higher.