What solar panel sizes should you buy?
There are many factors to consider when deciding which solar panel size is best for your needs and budget. We hope that the following article can help you make the right choice.
How to calculate the solar panel sizes for your household needs?
1. Evaluate your electricity bill
Energy bills are the best starting point to start. Most energy companies have a chart on the back of your bill that lists your average daily energy use. An energy-efficient average-sized house in Australia, with reasonable use of air conditioning and other appliances, typically consumes around 15kWh (kilowatt-hours) to 25kWh (kilowatt-hours) per day.
Depending on your location in Australia and the average amount of sunlight you receive every day, a 1kW solar power system typically generates around 4kWh to 5kWh of energy per day. PVWatts is a great tool you can use to estimate how much solar energy you can expect to produce if you use solar energy; This tool allows you to adjust variables such as system size and location.
2. Calculate how much electricity you use during daytime
Unless you have battery storage, your solar panels can only meet your electricity needs during the day. Unless you can get a generous solar feed-in tariff, when you use solar power directly, your solar energy is worth the most to you when you use it directly. The electricity from the solar panels will flow first to whatever appliance you are using in your home, saving you money by reducing the amount of electricity you need to buy from electricity retailers. Any surplus solar energy will enter the grid, and you will only get a net gain of 6-10c/kWh. This means that you need a solar system that can generate enough electricity to meet your energy use during the day.
This can be done most easily by estimating the percentage of total energy consumption that occurs when the sun is shining. For example, if you use an average of 30kWh of electricity per day but only use 1/3 of it during the day, you need a solar PV(photovoltaic) system that generates approximately 10kWh of electricity per day.
3. Choose a solar system size that will generate ample electricity to meet daytime demand
With an average daily household electricity demand of 25kWh, a 5kW solar system maybe probably the optimal size of a solar system: it would generate enough solar energy to offset part of the energy used during the day and does not “waste” by exporting solar energy to the grid.
The double hump electricity consumption pattern is common in families with school-age children. The highest power consumption time occurs outside the peak time of solar production.
On the other hand, a 10kW solar panel installation may be a bit too big for your home if there is no one inhabited during the day. However, if you are at home during the day, for example, if you are home office or retired, this may be a good choice.
The ‘day focus’ electricity usage pattern is common in retirees or families working from home. With the right-sized solar system, these households can easily use a large part of the solar energy they generate while sending only a small amount of solar energy to the grid.
4. Consider whether battery storage is a useful option for you
Not all solar PV systems are equipped with battery storage systems. These systems can actually be sold separately or retrospectively installed in existing solar systems. If you are interested in storing batteries for your solar system, there are many things to consider before making a decision. For example, what is your goal when installing the battery? Do you want to go off the grid or just save some solar energy for night use?
Knowing the answers to the above-mentioned questions will give you an idea of the ideal panel size for your electricity generation needs. Next, a professional installer needs to evaluate your roof architecture for some factors to see if and how to physically arrange the right number of panels on your roof to achieve your daily energy production goals.
Read our blog on How to choose the best solar panels for your property?