So, your considering powering you home with solar energy. Firstly, congratulations, you are on your way to becoming energy independent and helping the environment at the same time. Killing two birds with one stone you may say. One of the first things that should come to mind is “what size solar system should I install?” Contrary to popular belief, the size of your system is not decided by the size of your roof. The size of your solar PV system should be determined based on your energy usage, and how much you are prepared to spend.
Its generally recommended to consult a professional as your first point of call. However, it doesn’t hurt to have a little understanding beforehand. To make the process easier, we’ve broken down some of the main factors below.
What Is A KW And A KWh?
Most residential solar PV systems range from 1.5kW to 10kW – but what is a kW? If you’ve ever looked closely at your power bill, you’ll notice a measure of kWh (kilowatt hours); kWh is a unit of measurement that looks at the amount of energy you would use if you kept a 1,000 watt appliance running for one hour. It’s an average unit of measurement that power companies use to charge usage fees. However, solar systems measure energy in kW (kilowatts), not kWh. So what’s the difference? A kWh is a reflection of the amount of energy used. A kW is the rate of electricity usage. For a more detailed explanation Artisenergy provide a good insight.
How Many KW’s Do I Need?
This will depend on how much energy your house hold uses. Do you run a heat pump/air con system? perhaps you have a pool or spa? maybe both. These will cause a higher energy bill, meaning you may be looking at a 5-10kw system. If you do not have a high energy bill, a smaller system may suffice. However, with solar batteries becoming increasingly popular, most people will recommend a 5Kw system. A 5kW system is currently the largest you can install with out acquiring further consent. This will commonly be recommended by your installer.
How Many Panels Do I Need?
A common question asked is ‘how many panels do I need? This will first depend on the system size you choose. Bear in mind you do have options. Some panels are more efficient than others, meaning you will require less of them. For example; A 5kW system could be made up of 20 x 250W panels. It could also be made of 15 x 333W panels. It will come down to what option is best suited to your home and is something you will discuss with your installer.
What Size Solar System Should I Install?
There are current limitations on the size of system you are allowed to install. These limitations vary from state to state and also depend on whether you have 3 phase or single phase electricity. In most states, a 5kW system is the limit. If you would like to get more, you will need to be granted council approval. Recently NSW has amended the law, allowing larger scale systems to be installed without council approval. Read further about that in PV magazine‘s article here. This is great news for NSW residents and has been fueled by the increased demand for battery storage systems. It pays to research what your state’s guide lines are. For a basic guide you can check Solar Calculator .
Before installing a solar PV system, your supplier will complete what’s called a ‘home assessment’; a professional will visit you in your home, look at your recent and past energy bills to identify a usage pattern, assess your roof, and talk you through the best solution for your home. Our article on what to do before you solar home assessment will help you prepare for this assessment.
Now that you have that basic understanding, you can look at your energy bills in a new light and determine what your solar panel needs might be, based on your usage patterns.
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