Can I install Solar on my Roof?

Whilst most homes are suitable for solar installations, there are elements to consider when determining suitability for different rooftops including roof condition, material, size, orientation, and shading.

Some NSW home rooftops aren’t strong enough to support the weight of a solar system. Because the average 440W solar panel weighs around 21kg, a 6.6kW (15 panels) would result in 315kg of additional weight that your roof and structure will need to support.

If you’re stressing out about if your home’s roof is strong enough, it is most likely that your house can have a solar installed, depending on its age. I personally have a 30-year-old+ terracotta roofed house, and it can easily support my smaller 3.3kW solar system.

As solar is a long-term investment, your solar system will be installed for 25+ years, so if you have a suspicion that you’ll need to perform rooftop repairs, it’s far better to do so before your installation rather than paying more for a removal and reinstallation.

What’s the best Roof Type Material for Solar Installations?

I mentioned my solar installation in Newcastle was installed on terracotta tiles, but is that the best roof material for solar installations? No, terracotta and concrete tiles are generally more expensive to have a solar system installed on, due to having to lift and cut tiles, and the extra care needed to not break and replace broken tiles.

Metal roofing like corrugated and Colorbond steel are typically preferred by solar installers as they offer higher durability, panel mounting, and minimised penetration which can be a more cost-effective solar installation as opposed to tiled roofs.

Whilst most rooftop materials can have solar installed, it really comes down to which may be cheaper.

What House Orientation is Best for Solar?

In New South Wales, Australia, the sun rises in the east and sets in the west which makes a north-facing solar system optimal for average daily solar generation. A north facing system will also vary in its generation depending on the rooftop’s tilt.

The pitch, angle, or tilt of your rooftop will play a part in the total generation as the sun’s path and angle changes throughout the seasons in the year. Some rooftops may have a steep tilt, and others a flatter face which can both affect your seasonal solar performance.

A typical preferred roof tilt range varies between 15° - 30° which is typically ideal for most solar systems across Australia. Southern Australia can get away with having steeper roofs, and Northern flatter. A super-steep roof like anything over a 45° can affect summer performance as the sun’s path is higher.

(A solar system that is designed to shine at least one array directly at the sun at all times of the day. East, north, and west.)

Optimising Home Solar System Sizes & Multi-Arrays

So, your roof seems pretty suitable for a larger solar system, but what if you have a bunch of little roof faces and can’t fit one collective array? The good news is that solar manufacturers have been developing components that are designed for a range of multi-array configurations for years now to enable installations for a broad range of homes and businesses throughout Australia.

Solar systems can support multiple arrays that are installed on various roof faces using multi-MPPT string inverters. Microinverters are also used by different solar installers.

By supporting multiple rooftop arrays, you can expand your system in addition to your east and west roof faces, to take advantage of earlier morning and later afternoon sunlight. This means your multi-array solar system is optimised to generate solar energy even more than solely a north-facing solar system.

Why are Solar Systems Always North-Facing?

As we mentioned before, most solar systems in Australia are installed on the North(est)-facing rooftop to enable as much solar generation as possible. But doesn’t the sun go above the house? Would this hit all of my roof?

Whilst the sun may hit most of your home’s rooftop, solar is at optimal performance when direct sunlight is hitting the panels face on. This ensures your solar is generating at its fullest potential, helping you save.

Some homeowners opt-in for additional solar to take advantage of those times when a north facing system doesn’t hit optimal performance like early mornings and afternoons. Using this chart, you can see that sunrise starts at 63° and makes it way over to 297° as the sun sets. This means that the east and west-facing rooftops will have a duration of highest performance as it transitions to midday.

(A solar installation on a south-facing roof, tilted to face north towards the sun).

How are Solar Systems Optimised for Homes?

Arguably the most important part of your solar installation will the solar design phase, where elements like tilt, capacity, and orientation are optimised for your property specifically (or at least should be with good solar installers!).

Your solar system size will be determined by your budget, consumption habits, and roof real estate, which the ideal system could range from anywhere between 3.3kW to 15kW+ for the average home. Those with bigger budgets and requirements can opt in for ground mount solar systems where they can be scaled, only being limited to the amount of land real estate you’re willing to use.

For flatter roofs, installers may opt in for tilt mounting, where the panels aren’t just placed on your roof, but are on adjusted mounting to best tilt the panels towards the sun to maximise generation throughout the year.

What are Solar Trackers?

Designed mostly for commercial solar farms and large-scale ground mount solar, solar trackers are variable tilt mounting systems that directly tracks the sun’s daily movements to maximise solar generation for as long as the sun is out.

Because rooftop solar systems have fixed tilts, there are large portions of the day where the sun is hitting the panels at an angle. A tracker would adjust accordingly to help ensure the solar panels are directly facing the sun at all times of the day through single and dual-axis solar trackers.

Solar trackers are only really found for ground mounted systems like off-grid systems, solar farms, and other large-scale solar arrays, which can be designed to track east to west movement and others depending on the model and configuration.

Courtesy of Nextracker