Is My Roof Right for Solar?

Solar installers assess roof suitability as part of any proper site visit or desktop assessment. But having a basic understanding of the key factors means you can self-screen before even requesting quotes — and have a much more productive conversation with installers when you do.

Direction: Which Way Does Your Roof Face?

In Australia, the sun tracks across the northern sky, so north-facing roof sections receive the most solar radiation across the course of the day. A north-facing installation will typically generate more electricity annually than any other orientation. East and west-facing roofs also work well — east captures morning sun (useful for morning routines and overnight EV charging), and west captures afternoon sun (which can align nicely with higher afternoon electricity demand). South-facing sections are the least productive in Australia, but even a south-facing installation on a roof with good pitch and no shading can still generate useful amounts of electricity.

Many homes have multiple roof aspects, and a good installer will design a system that uses the best available sections, sometimes combining orientations across different roof faces. A split system (panels on two different faces) can actually smooth out generation across the day, which can be beneficial depending on your household's electricity usage timing.

Tilt: What's the Best Angle?

The optimal tilt angle for solar panels varies with latitude. In most Australian capital cities, a tilt of roughly 15–30 degrees is close to ideal for maximising annual energy production. Most residential roofs fall within this range naturally — a typical Australian home has a roof pitch of 15–25 degrees. Flatter roofs (including some commercial buildings with near-flat surfaces) can use tilt frames to angle panels appropriately, though this adds some cost.

Shading: The Most Important Factor

Shading is the factor most likely to reduce a solar system's performance significantly. Even partial shade on one panel can affect the output of other panels in the same string (a series circuit of panels). Modern solutions help mitigate this:

• Microinverters: Instead of one central inverter, each panel has its own small inverter. Shading one panel doesn't drag down the others.
• DC optimisers: Similar concept — each panel has an optimiser that maximises its individual output, reducing the impact of shading on the rest of the string.
• Smart system design: A good installer will design strings to avoid mixing shaded and unshaded panels where possible.

Common sources of shading to consider include large trees (particularly if they'll grow taller over time), neighbouring buildings or structures, chimneys, TV antennas, satellite dishes, and skylights. A shading assessment is a normal part of any quality solar site inspection.

Roof Condition and Material

Solar panels are typically installed using rail mounting systems that attach to the roof rafters beneath the surface. Common roof materials — concrete tiles, terracotta tiles, corrugated Colorbond steel, and tin — are all routinely used as solar bases. Asphalt shingles (less common in Australia but found in some homes) also work fine. The condition of your roof matters more than the material: if your roof needs re-roofing in the next five to ten years, it's often sensible to do that work before installing solar so you don't have to pay to remove and reinstall panels later.

Roof Size and Available Space

A standard residential solar panel today measures roughly 1.7 metres by 1.1 metres and produces about 400–440 watts of power. A 6.6 kW system requires roughly 15–16 panels, needing approximately 25–30 square metres of usable, unobstructed roof space. Most Australian homes have more than enough roof space for a well-sized system, though heavily segmented roofs with multiple chimneys, skylights, or other protrusions can reduce available area.

Heritage, Strata, and Other Restrictions

If your home is on a heritage register, in a heritage overlay area, or part of a strata-titled complex (such as an apartment or townhouse with a body corporate), there may be additional approvals required. Heritage restrictions vary significantly — some permit solar if panels are not visible from the street; others are more restrictive. Body corporates have their own approval processes. These situations are manageable but require checking before you proceed.

The bottom line is that most Australian homes are excellent candidates for solar, and even imperfect roofs can often be accommodated with thoughtful system design. A professional site assessment by an accredited installer will give you a definitive answer for your specific roof — and most installers offer this assessment at no cost.