Seasons & Panel Efficiency
As the amount of sun varies over the seasonal weather changes. In summer, days are longer, and in winter they are shorter. This means your solar system will be able to generate more energy in the summer days than in winter.
We are fortunate to live in Australia, where sunlight does not differ extensively between summer and winter. Australia is undoubtedly one of the most sunniest countries in the world, therefore the output for solar is impeccable.
Due to the movement and angle of the sun changing throughout the day, the strength of the sun’s irradiance varies and therefore, the amount of electricity generated by your solar system. The optimal time for producing solar energy is from around 10am – 3pm Perth time.
Roof angle and orientation and location of your home can have an impact on the efficiency of your system, and how much energy your panels can generate. The optimal position for panels to be in is when they are positioned perpendicular to the sun. This means the sun rays hit the PV panels on a 90° angle. North angled rooftops have the best performance and generate the most, particularly in southern hemisphere countries like Australia. Perth Solar Force has a great tool to accurately calculate the optimal position of your panels. Your rooftop orientation and angle of the roof need to be combined to measure the solar output potential of the panels, at the property location, and we use a tool called Nearmaps to help determine this.
Panel directions and the type of household’s various orientations generally best suit are given below:
North Facing Panels: North facing panels will produce the highest amount of power/kWs per day. This is because the sun is at its highest and brightest in the middle of the day, targeting the north facing roof and solar panels. This is the best option for people who are at home during the middle of the day or for businesses with high power demands during the middle of the day.
North / North-West Facing Panels: West facing panels generate the most amount of power in the afternoon, due to the sun setting in the west and will obtain all of the afternoon sun. West panels may produce 5-12% less electricity compared to if your panels were installed on the north facing side of the house. However, some houses do not have room on their north facing roof, so this is the next best alternative. West facing is best for households utilising more energy in the afternoons than in the mornings, e.g. when you get home from work.
North / North-East Facing Panels: Panels facing East to North east are similar to panels facing North to North West and will produce pretty much the same amount of power, which again may be 5-12% less compared to north. This option is ideal for people who are home in the morning as the sun rises in the east so then you will get more morning production. This is great for earlier risers, or energy use in the mornings.
East and West split Panels: Directly east and direct west facing roof may produce around 12% less than north facing panels. The east/west split does have the advantage of producing power all morning on the east side, all afternoon on the west side with for most months of the year, having all the panels getting hit by the sun during the midday. This will help with a constant number of panels producing throughout the day from sun rise to sunset instead of a heavy concentration for north panels in the middle of the day.
South Facing Panels: As Australia is so far south of the equator, south facing panels are the least ideal. In the summer time when the sun is directly above your house, south panels may produce just as much power as the north panels. But outside of these months, such as spring, autumn and especially winter, the south panels will more than likely produce very little to no power. Typically, south facing panels will produce up to 30% less a year.