With interest in home solar systems soaring, households need to take a step back and look at the structure of their homes to ensure they get the most return from a solar investment. That’s according to Standard Bank’s home efficiency platform, LookSee, which has developed SA’s first free solar score for residential properties. 

“The location, conditions and structure of a home have a very real impact on how effective a solar system can be. This is why homes with the same system will often generate different amounts of electricity,” says LookSee’s executive head, Marc du Plessis.

Understand your roof’s solar potential with a free solar score from LookSee

The free and easy-to-use solar score requires only a physical address to generate and assess a 3-D model of the home. The user is then presented with a solar score out of 100, usable roof area, average sunlight days, generation potential, and how much the household could save on their electricity bill. 

While comparing solar system types is fairly easy, assessing the structure of your home to understand what to expect from a solar installation is far more complex, says Du Plessis. A variety of factors affect solar performance, and it’s rare for a home to have perfect conditions or a solar score of 100.

The main factors that play a role in the performance of a solar system include:

• Roof direction: In SA, the best direction for solar panels to face is north as it means the panels have direct access to sunlight throughout the day. Solar panels can still be installed on roofs facing east or west, but their generation potential will be lower. South-facing roofs are not suited for solar panels in the southern hemisphere. 

• Roof angle: This is mostly an aspect that households can do little about unless they have a flat roof on which solar panel mounting structures will be installed. If this is the case, your installer should work to the panels being positioned at an angle of between 30° and 45° to ensure they receive maximum sunlight. 

• Obstructions: Shady conditions significantly reduce a solar panel’s ability to capture and convert sunlight into power. Ideally, there should be no trees, buildings, mountains or other structures surrounding the home. If you can't remove or minimise the obstructions on the optimal side of your roof, you may have to look at one of the east- or west-facing sides or consider a free-standing installation. 

• Roof size: Once you have determined the optimal side of your roof for solar panels, it’s time to consider the space you have to work with. The larger the roof area, the more space you’ll have available for the installation of solar panels, resulting in higher electricity generation. If your roof space is limited, you could consider higher-efficiency panels or select smaller panels to make the most of your roof. 

• Solar irradiation: This refers to the power of the sunlight or the level of photovoltaic emissions that a home receives and determines how much energy is available to be converted into electricity. SA's geographical location and weather patterns mean the country generally experiences generous levels of solar irradiation, but areas in the Northern Cape score highest in this factor. 

"You don’t need a perfect solar score to benefit from a solar installation. We only consider scores lower than 20 as unfeasible. But knowing your score, and your home’s generation potential, can help you make an informed decision about the size and makeup of your solar solution," says Du Plessis. 

The LookSee solar score covers metropolitan cities in Gauteng, KwaZulu-Natal and the Western Cape. Work is under way to extend the coverage to all towns and cities in SA during 2024 as well as adding sectional title properties. 

This article was paid for by Standard Bank.