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How many solar panels do I need?

When considering a solar panel installation, homeowners want to figure out the size of solar system they want, in order to plan their solar project accurately. The number of solar panels required is one of the main considerations to make to ascertain the total value of their solar venture. There are various factors that influence the number of solar panels required to fulfil your energy needs which we discuss in this article.

How to determine the number of solar panels you need

Energy usage

The size of your solar panel installation directly depends upon your electricity consumption. You want to ascertain how many watts of power you use per hour and collectively in a day. Your total energy needs will also depend on whether you want an off-grid or a grid connected solar panel installation. You can find the number of panels you require by multiplying the watts of power you consume every hour by the number of sunlight hours in your area, and dividing the product by the panel’s wattage.

Family size

The number of people inhabiting the property will also influence the size of your solar panel installation. An average Australian household with a medium sized family is usually recommended a 6.6kW solar system to begin with. An average family would require 22 solar panels of 300W power output each, for their energy needs. More number of panels are required to cater to the energy needs of bigger families and houses.

Roof space

The size of your solar panel installation will also depend on the amount of roof space you have, to mount the solar panels. if your roof cannot accommodate a desired number of panels, you can go for panels of higher wattage and/or efficiency to receive more output from fewer panels.

Roof location and orientation

Solar panel installations are faced north in Australia for receiving maximum sunlight and producing maximum solar energy. If your property location is such that the solar panel installation cannot face north, the next best direction options are east and west, however, the number of solar panels required could change for different directions as the total power output will be different. Another important factor to consider is the optimum tilt angle for solar panels in Australia. Solar panel installers typically recommend an optimum tilt angle for solar panels in Australia between 10 to 30 degrees.

Panel wattage and efficiency

The power output you receive from a solar panel installation depends on the power wattage and efficiency of each panel. When you opt for solar panels of a higher wattage and efficiency, the number of solar panels you will need for a desired output will be lesser as compared to solar panels of lower wattage and efficiency.


In addition to all the factors discussed above, shading on your roof will reduce the output of the affected panels thereby reducing the overall output of the system. So, you can take care to trim the trees and remove the objects that cause shade to maximize solar yield from fewer panels. The number of solar panels you install can be fewer if you are choosing a grid-connected solar panel installation as some of your power needs can still be covered by grid supply. However, if you are opting for a completely off the grid system, then you would require more solar panels to be self-sufficient.

Contact Solar Power Nation for genuine and best solar deals in Australia on top quality premium and value for money solar equipment. We hire only CEC-approved solar panel installers to do the jobs.

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