How Many Solar Panels Do I Need in Australia 2026: Calculator Guide

Getting the solar system for your home is the smartest way for you to cut down on your electricity bills without overspending. But different households have different energy needs, and the number of solar panels you need will depend on your specific energy consumption. In Australia, most homes require approximately 10–25 panels on average to meet their energy needs.

In this post, we break down everything you need to get the right size solar system. We will take a look at household consumption as well as sun exposure and solar panel wattage. We will delve into a simple step-by-step calculation method and look at some practical examples for small, medium, and large homes.

We'll also take a look at some portable solar options that are great for renters, travellers, or people who live off-grid, such as the full BLUETTI portable solar panel range. By the end of this post, you'll know exactly how many panels you need and some great alternatives if rooftop solar isn't an option for you.

Key Factors Influencing Your Solar Panel Needs

There are several factors that determine how many solar panels your home needs, and understanding them will ensure you get a solar system that fits your energy requirements.

1. Household Consumption

The electricity use varies by the size of the household:

• 1–2 people: 15–20 kWh/day

• 3–4 people: 20–30 kWh/day

• 5+ people: 30–40+ kWh/day

Take your Quarterly electricity bill and get the average daily consumption in kWh by dividing the figure by 90. If you own things like a pool pump or an electric vehicle, then you'll also need to add 20–30% extra.

2. Location & Sun Exposure

The peak sun hours will depend on your region and will differ across Australia:

• QLD/NT: 5–6 hours

• NSW/WA: 4.5–5.5 hours

• VIC/SA/TAS: 4–5 hours

Roofs that are built facing the north get the most sunlight, and note that shade from trees or nearby buildings will reduce sun exposure. This can significantly lower electricity production by up to 20–30%.

3. Available Roof Space

A standard-sized solar panel needs roughly 1.7 m² of roof space. Depending on your electricity needs, you may require anywhere from 15 to 50 m².

4. Solar Goals

You need to ask yourself, do you want to:

• Offset your electricity bills fully?

• Reduce the electricity cost partially?

• Pair the solar panels with a battery for greater energy independence?

The answers to these questions will determine the size of the solar system that you'll need.

5. System Efficiency

Note that solar systems will experience efficiency losses from the sun's heat, wiring, shade from nearby structures, the position of the roof to the sun, and inverter conversion. This is why you should plan for efficiency levels of 75–80% with your solar system.

Panels also experience wear and tear over time, usually around 0.5% per year, so it makes sense to size your solar system slightly higher for long-term performance.

By understanding the above factors, you can pick the right solar system that meets your home's energy needs.

Step-by-Step Calculation Guide

Choosing the right size for your solar system doesn't have to be complicated; it's straightforward if you follow the formula below.

1. Find Your Daily Usage

You can know this by reading your electricity bill:

Daily Usage = Quarterly kWh ÷ 90

Example: 1,800 kWh ÷ 90 = 20 kWh/day.

2. Determine Peak Sun Hours

You can use approximate values of where you live:

• Brisbane – 5.5 hrs.

• Sydney – 5 hrs.

• Melbourne – 4.2 hrs.

• Perth – 5.8 hrs.

3. Apply System Efficiency

Divide your solar system's output by 0.75–0.8 to account for system losses.

4. System Size Formula

Solar System Size (kW) = Daily Usage ÷ No. of Sun Hours ÷ Efficiency of System

Let's consider this example for Sydney:

• Daily usage – 20 kWh

• Number of sun hours – 5

• Efficiency – 0.75

20 ÷ 5 ÷ 0.75 = 5.33 kW system

5. Converting kW to Number of Panels

Solar Panels Needed = Size of System (kW) × 1000 ÷ Panel Wattage

For the Sydney example above, and assuming you are using 400W solar panels:

5.33 × 1000 ÷ 400 = 14 panels

Examples for Different Household Sizes

1. A small household located in Brisbane that uses 15 kWh/day

Number of sun hours = 5.5 hours

15 ÷ 5.5 ÷ 0.75 = 3.64 kW

This time let's assume 350W panels: 3.64 × 1000 ÷ 350 = 10–11 panels

2. A medium household located in Melbourne and using 25 kWh/day

Number of sun hours = 4.2 hours

25 ÷ 4.2 ÷ 0.75 = 7.94 kW

If they use 400W panels: 7.94 × 1000 ÷ 400 = 19–20 panels

3. A Large Household using up 35 kWh/day in Perth

Number of sun hours = 5.8 hours

35 ÷ 5.8 ÷ 0.75 = 8.05 kW

Let's assume 450W solar panels: 8.05 × 1000 ÷ 450 = 17–18 panels

With the method above, you can easily find out your exact power needs depending on where you live.

Solar System Recommendations by Household Size

Being able to choose the right number of solar panels becomes easier when you know how to match system size to your household's power needs. Granted, every home is unique, so the ranges help to provide a basic estimate based on the typical Australian home energy consumption and roof space.

1–2 Person Household

Smaller homes that are more energy-efficient will normally use 15–20 kWh/day. This would make such a household well-suited to a 3–5 kW solar system, which would translate to around 8–13 400W solar panels.

And the required Roof space for such a system would be small, at roughly around 14–22 m². For such a solar system, the total installation costs would lie between $4,000 and $7,000 after STCs.

This size solar system would comfortably power general appliances, lighting, and refrigeration, plus moderate daytime power consumption.

3–4 Person Household

A typical family in Australia uses between 20 and 30 kWh/day, which would make a 5–8 kW system ideal. This would translate to 13–20 panels, which would need 22–34 m² of roof space. The installation costs average about $6,000 to $10,000, of course, depending on the quality of the solar system and type of inverter used.

Such a solar system would suit families that have frequent daytime power needs, plus run power-hungry appliances like dishwashers and dryers.

5+ Person Household

The Larger Aussie households will tend to use about 30–40+ kWh/day, which means they would need an 8–13 kW system. This translates to 20–33 panels and about 34–56 m² of roof area. The cost of such a system would range between $9,000 and $16,000.

These types of solar systems offer larger homes the capacity they need for high power usage, including all-electric living.

But there are some special situations.

If you have:

• Pools – Add in an extra 2–3 kW

• EVs – Add an extra 3–5 kW

• All-electric homes – Increase the system size by 20%

By keeping your future power needs in mind when getting your size solar system, you can ensure long-term savings, more efficiency, and greater energy independence.

Exploring Panel Wattage Options for Optimal Performance

The solar panel wattage will determine how many panels you'll need, as well as how much roof space is required. Most Aussie households will typically choose solar panels that are between 350W and 500W.

350–400W Panels: Balanced and Reliable

Solar Panels that are in the 350–400W range are the preferred choice for residential solar installations in Australia, thanks to their efficiency and affordability. Plus, they are also able to offer great performance in a variety of climates.

A standard 6.6 kW system connected to a 390–400W panel will require 16–17 panels. This suits the area of medium-sized roofs in Australia and can deliver reliable output throughout the round. The solar panels are a great choice for homeowners who want a cost-effective and reliable solar system.

450–500W Panels: High Efficiency With Fewer Panels

That said, the larger 450–500W modules have also seen a steady increase in popularity due to their ability to produce more electricity with fewer panels. This is especially ideal for smaller homes that have limited roof space or homes with roofs that experience shaded sections.

A 6.6 kW system that is connected to 500W panels will require just 13–14 panels. This will help free up roof space in case there are any plans for future expansion. And sure, such solar panels will cost more upfront, but they offer long-term advantages, especially in high-heat environments where efficiency is important.

300–350W Panels: Budget-Friendly and Flexible

Smaller wattage Solar Panels, like the 300–350W options, remain a cheaper, easily available alternative, even though they will require more roof space per kilowatt. That said, these are a practical choice for homes with large roofs, sheds, or even homeowners on a budget. And since you will require more panels, keep in mind also that you'll need more mounting equipment, and the labour costs may increase slightly. That said, the lower price of the solar panels will often offset the difference.

Choosing the Right Wattage for Your Setup

There are a couple of factors to look out for when deciding on the right wattage for your solar panel:

• Roof Space — 450–500W solar panels are great for homes with a smaller roof space, while 350–400W panels will do well on homes with more space on the roof.

• Budget — the panels with higher wattage will also be costlier. However, you will need fewer units.

Portable Solar Panel Options

Portable solar panels offer an excellent alternative for Australians who aren't able to install rooftop systems or are looking for more flexibility. They offer clean, renewable power, and the good part is that you will not need any approvals.

More and more households, travellers, renters, and those living off-grid are finding out that portable solar offers independence, is convenient, and works where traditional rooftop solar isn't suitable.

When Rooftop Solar Isn't the Right Fit

Portable solar can prove to be a highly practical solution in a wide range of situations, such as:

• When living in Rental properties, where making permanent installations isn't allowed.

• When living in Apartments, with no easy access to roofs.

• On Temporary locations, such as during short-term home stays or when on remote worksites.

• When looking to supplement existing solar systems, and there is no more roof space.

• When off-grid, such as during camping or overlanding.

• When in need of emergency backup power, such as during outages.

Discover BLUETTI's Portable Solar Panel Lineup

BLUETTI 60W Solar Panel

This portable, not forgetting lightweight, charger is designed for charging small devices. This makes it perfect for phones, tablets, GPS units, and power banks, and thanks to its size, it is ideal for hikers and backpackers.

And since it's compact, it comes with a foldable design for easy carrying. This 60W panel ensures that your essential devices stay charged even when you find yourself in remote locations.

BLUETTI 100W Solar Panel

The BLUETTI 100W panel is a well-balanced all-rounder that offers even more power without compromising on portability. It is capable of charging small to medium-sized BLUETTI power stations, making it an excellent addition for weekend camping or van life. What's more, its portability-to-output ratio has turned the 100W solar panel from BLUETTI into one of the most popular choices.

BLUETTI PV100FX Flexible Solar Panel

This 100W flexible solar panel by BLUETTI offers a unique and highly adaptable solution. Thanks to its flexible design, you can place it on curved or uneven surfaces.

The PV100FX is great for boat life, caravans, RV roofs, and camper trailers, as it is both lightweight and weather-resistant.

BLUETTI 120W Solar Panel

Next on the list is the compact yet powerful BLUETTI 120W panel that gives you faster charging for your larger devices. It is an excellent choice for those extended camping trips and will charge your portable power station faster than the 100W models.

And yet the BLUETTI 120W solar panel is still easy to fold and simple to transport, which also makes it a great mid-range panel option for travellers who require consistent off-grid power.

BLUETTI 200W Solar Panel

Then there is the 200W panel, offering you a portable solution to satisfy your greater energy needs. This solar panel is perfect when off-grid, when doing remote work, and for 4WD setups.

The BLUETTI 200W solar panel can also power small appliances directly through a power station and offers fast charging for the power station.

BLUETTI 350W Solar Panel

It comes with a high-capacity output and is a good choice for those looking for permanent off-grid solar setups. The 350W panel can also be configured in multiple-panel arrays to power sheds, cabins, or even large camping setups.

If you need powerful charging and don't want to install rooftop solar, then the BLUETTI 350W solar panel is worth a look.

BLUETTI 500W Solar Panel

If you want even more output, you may want to check out the BLUETTI 500W solar panel. It is their most powerful portable option and offers a perfect option for a dependable energy backup solution for tiny homes and remote cabins.

FAQs

Q: Can I install solar panels myself?

A: No. In Australia, you need to involve a Clean Energy Council (CEC)–accredited installer to help you install rooftop solar. This helps to ensure that the installation is safe and is compliant with Australian Standards, as well as helping to protect the equipment warranties. Furthermore, it is also essential for STC (Small-scale Technology Certificates) eligibility, which brings down the upfront cost of installing a new solar system by a significant margin.

Q: What happens to excess solar power?

A: Any extra electricity can be sent back to the grid, which earns you feed-in tariff credits from your retailer. Homeowners who also have a battery system in place can also store the excess energy to use during nighttime or during power outages. If you choose to export excess power or store electricity in your battery system, it all comes down to the tariff rates as well as your overall energy goals.

Q: Do solar panels work on cloudy days?

A: Yes. Solar panels are still able to generate energy on cloudy days, but the productivity drops to 20-25% of their optimal output. That said, the great thing is that since Australia has high solar irradiation, it means that cloudy days have minimal impact on long-term electricity generation.

Q: How long do solar panels last?

A: The vast majority of modern panels will last you anywhere from 25 to 30 years or more. The manufacturer will usually offer a performance warranty that guarantees around 80% of their original output after 25 years of constant use.

Q: What maintenance is required?

A: Solar panels need very little maintenance, often requiring just occasional cleaning to remove dust, leaves, or debris to help maintain the panels' optimal performance. It is also recommended that you have an annual inspection done by a qualified technician to help ensure everything remains safe and efficient.

Q: Will solar panels damage my roof?

A: No, not when they are installed the right way. Panels will be mounted on the roof using methods and systems designed to protect the roofing materials, and will protect the covered area from the sometimes harsh weather.

Q: Can I take my panels with me when I move?

A: Yes, you can, but keep in mind that removing and then reinstalling the solar system can be costly. Installing solar panels will also increase your property value, so homeowners generally prefer to leave the system in place.

Q: Do I need planning permission?

A: Most of the homes do not require council approval, but the rules may vary for heritage-listed houses, apartment buildings, and some local councils, so it's always best to check first.

Conclusion

To choose the right number of solar panels, you first need to understand your energy usage, the number of hours of available sunlight, the available roof space, and your long-term goals. The majority of Australian homes require about 10–25 solar panels. That said, keep in mind that the actual number will depend on the size of the solar system, solar panel wattage, and whether you want to completely offset your electricity bills or just reduce them.

By using the formula we went through in this post, you can calculate your home's ideal system size with confidence. And if installing a rooftop solar system is not a practical choice for you, or if you want more flexibility, then consider BLUETTI's portable solar panel range for more flexibility and installation-free options.

Whether you choose a full rooftop system or prefer a portable BLUETTI setup, smart solar sizing ensures maximum savings and independence for years to come.