Guides

Choosing solar panel orientation and tilt

Published 8 October 2026. About 7 minutes to read.

For the most energy over a year, panels face the equator and tilt at an angle close to the site's latitude. In practice the roof decides most of it, and the right answer also depends on when the household uses electricity.

Facing the equator

In the southern hemisphere, panels produce the most when they face north. In the northern hemisphere, south. Lekker Sun, like most design tools, measures the azimuth as a compass bearing: 0° is north, 90° east, 180° south and 270° west.

Turning panels away from the equator costs less than many people expect. Up to about 30° off due north or south, annual losses at moderate tilts are usually only a few percent. East and west roofs lose more, typically in the range of 10 to 20 % compared with the best orientation, depending on tilt and latitude. Flatter panels lose less when facing east or west.

Tilt

For the most energy over a whole year, a tilt near the site's latitude is a reasonable starting point, usually slightly flatter in sunny climates. A steeper tilt favours winter, a flatter tilt favours summer. On pitched roofs, panels normally follow the roof pitch, and the difference between a 20° and a 30° roof is small compared with orientation and shading.

Very flat panels (under about 10°) do not self-clean well in rain, so dust and debris build up along the lower edge.

When east and west make sense

Annual energy is not the only goal. If a household uses most of its electricity in the evening, a west-facing array produces more of its energy when it can be used directly, which reduces how much has to go through a battery or be exported at a low rate. East and west arrays together give a flatter production curve, with less at midday and more in the morning and late afternoon, which can also let you fit more panels on a smaller inverter.

Compare the options on the cost of the energy the household actually saves, not only on kilowatt-hours a year.

Row spacing on flat roofs

Tilted rows on a flat roof shade the row behind them when the sun is low. A common rule is to keep rows free of shading for the middle part of the day in the depth of winter. For a row of depth L tilted at angle β, with the sun at altitude α at the time you choose, the distance from the front of one row to the front of the next is roughly:

row pitch = L × (cos β + sin β ÷ tan α)

For example, panels 1.76 m deep at 15°, with a design sun altitude of 25°: 1.76 × (0.966 + 0.259 ÷ 0.466) = 2.68 m from front to front. Lower tilts allow much closer rows, which is why flat-roof systems often use 10° to 15° and fit more panels in the same space.

This rule ignores the sun's azimuth, so it is a starting point. Check the actual shading at the times that matter.

Comparing options in Lekker Sun

Place an array on a pitched roof and, with snap to roof face ticked, it takes the pitch and faces the slope it sits on. On a flat roof or the ground, set the azimuth and tilt yourself. Draw two layouts as separate arrays, simulate the year, and compare their yearly energy and shading loss. The Finance page then shows how much of that energy the household uses directly.

This guide is general information to help you plan and compare options. It is not engineering, electrical or financial advice. Always follow the equipment manufacturer's instructions and your local wiring rules, and have a qualified installer check the design.