With the ever-increasing cost of electricity and an ongoing push for sustainable living, many homeowners are turning to solar power as an effective solution. When people start to think about installing solar, one of the most common questions they ask is “How many solar panels do I need?” The answer will vary based on a few different factors and requires some calculations to figure out. We’ll walk you through this process, so you’ll know how many panels are needed for your household.
Find out your household’s energy consumption
The first step in determining how many solar panels you need is to find out how much electricity your household uses. This is typically measured in kilowatt-hours (kWh). You can find this information on your past electricity bills, which detail your monthly and annual usage. An average Australian household consumes 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 energy usage habits. It’s best to look at your electricity usage across multiple months as you may use more energy at different times of the year (e.g. Winter). Identifying your typical usage is critical to estimating the number of solar panels required.
Learn your location’s peak sun hours
Peak sun hours refer to the average amount of sunlight received per day, which influences how much power your solar systems can generate. Perth enjoys numerous sunny days, making it an ideal location for solar power. According to the Australian Bureau of Meteorology, Perth receives an average of 5-10 sunlight hours per day. This means your solar panels will produce their rated peak output for this duration.
Deciding on solar panel size
Not all solar panels are created equal. Different solar panels have varying levels of efficiency and output. Efficiency is determined by the panel’s ability to convert sunlight into usable electrical power. A solar panel’s watts (W) is the maximum power output the panel can produce. If you know the exact type of solar panel you want, find out its wattage and use that number. If you’re unsure of which panels you want most modern solar panels have a wattage of around 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.
Other Factors to Consider
- Roof Space and Orientation: The amount of roof space available and its orientation (north-facing is optimal in Australia) significantly impacts the number of panels you can install.
- 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 electric vehicles or installing a pool.
Consulting a Solar Specialist
While you can make calculations yourself, we recommend consulting with a solar system installer. They can provide a more accurate assessment based on a comprehensive analysis of your location, roof orientation, shading issues, and specific energy requirements. Perth Solar Force specialises in tailored solar solutions and assists in finding the best system for your household.
The process of determining the number of solar panels required to power your house involves evaluating your energy needs, solar panel efficiency, peak sun hours, and several other factors. Engaging with professionals like those at Perth Solar Force can provide a more personalised solution ensuring that you harness the maximum potential of solar energy, leading to a sustainable, energy-efficient home.