A big part of installing solar systems is placing solar panels on your rooftop. If you see your friends and family with similar solar installations, you know they have multiple solar panels on their roof placed side-by-side. Some houses have large numbers of solar panels while others don’t seem to have as many. It makes you wonder how many solar panels you need for your house.
You must purchase a solar system that produces enough energy that matches your energy consumption, such as a 10 kW system. With a 400 W panel, you would need 25-26 panels to generate enough energy. You will need more panels if you aren’t using much power during the day, and you have storage options for night time usage.
For a 2 bedroom house, you should get a 4 or 5 kW system that would require 10-13 panels. A 3 bedroom house would require a 6 or 7 kW system with at least 15 solar panels. 4 bedroom houses would benefit from an 8 or 9 kW system with at least 20 solar panels.
How much energy is your house consuming?
Before you start thinking about the solar system you want, you must find out what your average daily energy consumption is. If your system isn’t generating enough power to meet your energy needs, it won’t help you save money or improve your energy efficiency.
Look at your energy bill or your energy provider’s app, such as AGL, to see how much energy you are consuming. The amount of energy used should be in kilowatt hours (kWh), which reflects your total energy consumption over the month. Divide that by the number of days to get an approximate number of your daily energy usage.
When do you use the most power?
The number of solar panels you need is also dependent on your energy consumption throughout the day. Solar panels generate the most energy during the middle of the day (12-1 PM), and they don’t generate any power at night. The technical term is the load profile, but knowing the time you use the most energy is important to determine the number of panels and where on the roof they should be located..
If you use most of your energy during the day as you stay at home, then you won’t need as many solar panels to provide power. Most of that power won’t be going into the grid and providing a feed-in tariff. You will be able to utilise that power properly and will save more money through your solar system.
A working professional who comes home at night and consumes most of their power then will not have much solar power to draw on. Investing in solar batteries such as the sonnenBatterie Evo and supplying it with power will be necessary to make the most of your system. Then you will require more solar panels to store enough energy to power your evening usage.
Check your energy consumption habits and ensure that you are confident when you use the most energy. That helps you decide how many panels you should get and what additions you should make to justify the panels.
What is the efficiency of the solar panels you will use?
Solar panel efficiency refers to the amount of sunlight that a solar panel can convert into electricity. The higher the number, the more sunlight you can convert to reach your power consumption needs. The more efficient a solar panel is, the fewer solar panels you need to generate your energy target. When looking at solar panels, you can see how much energy they can convert in watts (ie. 400 W).
Solar panels such as Q Cells’ Q.MAXX BLK-G4+ have a 20.8% efficiency rating and can produce up to 400 W of power. If you wanted a 5 kW solar system, you would need around 13-14 Q.MAXX BLK-G4+ panels to generate enough energy. A 10 kW solar system would need 25-26 of the same panels.
While solar panel efficiency isn’t the only factor you should look at, it’s important to know how much energy it can produce. That helps you figure out the number of solar panels necessary to power your house.
How large are the solar panels you plan to use?
Large solar panels can capture more energy and you won’t need as many for your rooftop. This also means you won’t need as many panels to power your system. Always check the measurements of the solar panels you are interested in to ensure that they will be suitable for your budget.
The average solar panel length is between 1.7m x 1m, with the Q.MAXX BLK-G4+ being around that size. Larger panels will go above that size and are more expensive to purchase. Installing them can also be a challenge since they take up more roof space. Consider how much energy they would be generating and if you can place enough on your roof to generate that power.
The average roof size in Australia is 200 square meters, and not all of it will be used exclusively for panels. That should fit the average solar panel well, but larger panels may have greater difficulty in fitting.
Does your roof have enough space for solar panels?
The size and weight of solar panels are important because your rooftop should be able to support their weight without collapsing. You also want your solar panels fitting on your roof to wire them together in a series or parallel formation to maximise your energy output.
Depending on your existing roof attachments and other objects, you are unlikely going to have your solar panels all in one line. If you had a 10kW system with 25-26 solar panels, you must have enough room to support them in a few rows around your roof. You should look at any potential obstructions or antennae that could interfere with installation.
If objects frequently fall or there are parts of your roof that are unstable, you want to avoid putting solar panels there. You should also ensure your solar panels have enough room for a proper tilt and alignment without obstructing each other.
Using the Q.MAXX BLK-G4+ panel as an example, it weighs 20.9 kg. Installing 25-26 panels means adding around 525 - 546 kg on your rooftop. Make sure that your rooftop can support that weight or distribute it elsewhere to ensure you don’t compromise the roof’s integrity.
Is there significant shading around your house?
Shading prevents your solar panels from receiving enough sunlight to meet your power needs. While some shading might be unavoidable (like from clouds), you should look for nearby sources of shade that could block a significant part of your rooftop. Trees and other buildings are examples of shade that can impact your solar generation.
If you can remove these sources of shade, like cutting tree branches, it’s something you should do before installing your solar system. For more permanent sources of shade such as a building, you should look at alternative places on your rooftop where you can install solar panels. If cloud cover prevents you from getting much sunlight at all, invest in high efficiency panels to get more energy with less sunlight.
You should also make sure that your solar panels are clear of objects like leaves that could cover them. Move your solar panels to alternative locations or make sure you can easily clean up any cover. If shade isn’t addressed, your solar panels will generate less energy and they won’t meet your energy needs.
What direction will your solar panels face?
Your solar panels should be facing north because your panels will get greater exposure to the sun when they face that direction. This will also affect the tilt of your solar panels, which help capture sunlight according to the sun’s movements throughout the day.
Solar panels can also face east if you use more power in the morning, since they generate more power during that time. West-facing solar panels generate more power in the afternoon and are perfect if that is the time you use the most energy.
Depending on the location of your home and your existing rooftop installations, you can’t have all of your solar panels face true north. Having many panels facing that direction is better and you can have other panels face other locations as well.
How many solar panels do you need to power a 2 bedroom house?
The average yearly power usage of a 2 bedroom house in South Australia is approximately 4,514 kWh, which means daily power usage is approximately 12 kWh. It’s perfect for a retired couple who won’t use many appliances and likely won’t use many of them for an extended period of time. The appliance they are most likely to use is their TV, though they will use other devices as well. Some appliances they could use are:
To meet a 12 kWh daily usage, you would need a 4 or 5 kW solar power system. Using the Q.MAXX BLK-G4+ panel that produces 400 W of power, you would need at least 10 solar panels for the array. More might be needed depending on your power requirements or if you are installing a solar battery.
How many solar panels do you need to power a 3 bedroom house?
The average yearly power usage of a 3 bedroom house in South Australia is approximately 6,171 kWh, which means daily power usage is approximately 17 kWh. A young couple who are young professionals and thinking about growing their family, but won’t be home during the day. They might have an arrangement where someone works from home, using more power during the day. Some devices they may use are:
Generating 17 kWh of energy will require a 6 or 7 kW solar system. The Q.MAXX BLK-G4+ panel produces 400 W and you would need 15 solar panels for your rooftop. If you are not going to be home and most of your energy usage is at night, you may require a solar battery for your system.
How many solar panels do you need to power a 4 bedroom house?
The average yearly power usage of a 4 bedroom is assumed to be around 8000 kWh, which gives a daily power usage of 22 kWh. A 4 bedroom house will usually contain a family of four, with two adults and two children. At least one person will be home taking care of the house, using a moderate amount of power throughout the day. Peak usage will still be in the evening, when everyone is home. Some devices the family may use are:
Generating 22 kWh of energy requires an 8 or 9 kW solar system if not more. Using the Q.MAXX BLK-G4+ panel for reference, you would need at least 20 solar panels for your house. Given the high energy usage, you may want more panels throughout the day or for battery storage for evening power consumption.
It’s always important to determine how many solar panels would be feasible for your energy needs before installation. Buying too few solar panels won’t be enough for your home, but buying too many might exceed your budget.
Knowing the size of the system you want to install, as well as your average energy usage will help you find the correct number of panels. You should also consider whether your rooftop can support that number and if shade forces you to install panels elsewhere.
If you aren’t sure about the size of your solar panel system, you can always invest in a larger system with Go Sunny’s ANYTIME SOLAR. You can see the benefits of your solar system without a large upfront cost and pay it off with installments. Contact us today to learn more.