The number of solar panels needed for your home depends on your home’s size and electricity usage. Solar is one of the smartest investments you can make in the South West of Western Australia. With electricity prices rising, many homeowners want to know: “How many solar panels do I need?” This guide breaks down how to calculate how many panels you need and the factors that matter most in South West WA.
Find Out Your Household’s Energy Consumption
The first step in determining how many solar panels you need is to know how much electricity your household uses. This usage is typically measured in kilowatt-hours (kWh) and can be found on your past Synergy electricity bills, which detail your monthly and annual usage. An average Australian household uses about 15-20 kWh per day. However, this can vary based on factors like the size of your home, the number of occupants, and your specific energy habits. It’s best to look at your electricity usage across multiple months, as your energy use can change seasonally (for example, you might use more in Winter). Getting a clear picture of your annual usage is critical for accurately estimating your solar panel needs.
Find Out Your Peak Sun Hours
Peak sun hours are a simple way to measure how much sunlight and solar energy your location receives. It’s essentially an hour where the sun’s intensity is at its strongest, averaging 1,000 watts per square metre. This measurement helps you estimate how much electricity your solar panels will generate. South West WA enjoys numerous sunny days, making it an ideal location for solar power. For example, Bunbury receives an average of 5.2 peak sun hours per day. This means your solar panels will produce their rated peak output for this duration.
Decide Your Solar Panel Size
Not all solar panels are the same. Different solar panels vary in their level of efficiency and output. Efficiency is determined by the panel’s ability to convert sunlight into usable electricity. A solar panel’s watts (W) is a single panel’s maximum power output. If you know the specific solar panel you want, look up its wattage and use that number for your calculations. If you’re unsure of which panels you want, you can use an estimate. Most modern solar panels have a wattage of about 400 watts (0.4 kW).
Calculate How Many Solar Panels You Need
If you’re comfortable with some basic maths, you can estimate how many solar panels you need using this simple formula:
Number of panels = (Your monthly energy consumption (kWh) / Monthly peak sun hours in your area) / Solar panel wattage
For example:
Monthly energy consumption (1320) ÷ Monthly peak sun hours in your area (200). The resulting number is your estimated system size (kW).
1320 / 200 = 6.6 kW system.
6.6 kW system / 0.4 kW panel = 16.5 solar panels.
You would need approximately 17 solar panels to meet your energy needs.
Remember, this is just a rough estimate. You should consult a qualified solar installer for a more accurate figure. They can assess your needs and recommend the right system size for your home.
Other Factors to Consider
- Roof Space, Direction and Shading: North-facing roofs capture the most sunlight in Australia. A home with a north-facing roof will get more out of the same system than a shaded roof and therefore needs fewer panels.
- Seasonal Solar Output: Solar production varies with the season. Sunlight hours in Bunbury and Busselton can be almost halved in Winter. This means a 5 kW system may deliver 40 kWh on a summer day but only 17 kWh on a cloudy one. Designing for acceptable winter performance ensures year-round value
- Battery Storage: A solar battery can store solar energy for use during non-sunlight hours. This could alter the number of panels needed. Battery storage allows for greater energy independence and less reliance on the grid.
- Future Energy Needs: Consider any future changes in energy use that could increase your energy demand. This includes starting a family, getting an electric vehicle or installing a pool.
Consult With a Solar Expert
While you can make calculations yourself, we strongly recommend talking to a professional solar system installer. They can give you a much more accurate assessment based on a thorough analysis of your location, roof orientation, shading issues, and your specific energy needs. Southwest Solar Force specialises in tailored solar solutions and helps you find the perfect system for your household. So if you’re looking at installing a solar panel system for your home, get in touch with Southwest Solar Force.
