How do you determine the right size solar system for your house? The answer is much simpler than you think! Let's start by asking an important question. Why have solar?

The end goal is clear: Energy Freedom

What is your goal of having solar? Many get solar to save money on their electricity bills. For others, it’s all about saving the environment by using renewable energy. Both of these reasons are part of our goal which is called ‘energy freedom’.

What do we mean by energy freedom? Let’s start with the most exciting part: saving money. We want the freedom of having a tiny electricity bill or even better, getting cash back! Imagine you’re opening your quarterly electricity bills and see the number is next to zero. Wouldn’t that be terrific? That feeling of free energy is simply unmatched, especially when it is from your own roof.

Energy freedom also includes the protection that you get from electricity price rises and the complexity that comes with it. There’s no more worrying about the future prices of electricity because you can rely on your solar panels. The more solar panels you have, the more freedom and protection you have.

Even if saving money isn’t your priority, installing more solar panels gives energy freedom by reducing your household emissions. The larger the solar system, the more you are offsetting gas and coal which in turn creates a net zero carbon emission home!

Let’s see how two of the current most popular solar system sizes compare.

How much will a 6.6kw solar system save me?

table showing the differences in 6.6kW and 10kW solar system
table showing the differences in 6.6kW and 10kW solar system
Cost of electricity is 29¢/kWh
The household spends $1420/year on electricity
Feed-in tariff is at 11¢/kWh and declines annually

What size solar system do I need?

As seen from the data in the table above, the extra $4,380 for the larger system provides you with a good return on your extra investment. The larger system also means lower energy bills and is better for the environment (since the electricity you sell back to the grid will be used by your neighbours) in short more energy freedom.

A bigger system means bigger savings

The average solar system size is now 8.8kW as households want more freedom from the grid. This has increased from a meagre 4.5kW in 2014, and is expected to increase in future as we electrify our cars and homes. Besides, doesn’t it feel great when you’re making more savings and completely offsetting your emissions with a large solar system?

graph showing the trend in solar system sizes over a decade
Graph showing the average solar system size in Australia

When we say cover your roof, we really mean cover it entirely. Even if you’re going to install it on the South side of your roof. Solar Analytics analysis of the performance of our 30,000+ customers showed that the best performing systems financially have a mixture of orientations, ie. solar panels facing East, West and North to capture more of the morning and evening sun. And SolarQuotes analysis shows that even south-facing panels are still worthwhile provided there’s no significant shading (and you don't live in Tasmania with a steep roof).

In many cases, installing more solar panels (yes even on the South side of the roof) actually provides a better financial return than installing a battery. Of course, this will depend on your electricity usage and the available energy tariffs in your region, and will change if battery prices fall. Check out this article to see if it’s right for you to get a battery.

How big of a solar system do I need?

When it comes to deciding the right solar system size, it's crucial to consider your specific circumstances. While the battery savings can vary considerably, with payback periods ranging from as little as 7 years in a few cases, to over 15 years for others. Currently, investing in more solar has a better financial return for most homeowners, but this will depend on your personal circumstances. Before considering a battery, we recommend getting the biggest solar system you can fit on your roof!

Future-proof your home with abundant, free energy

Back in 2014, the average household solar system was 4.5kW. As of 2022, it’s 8.8kW. It has doubled in under a decade and it is likely to increase in the future. The solar system size that is adequate today will not be enough in the future. Why? Let’s take a look at what’s going on in the near future.

Your electricity usage is likely to increase by switching from gas hot water to electric hot water like a heat pump, if you swap from gas to induction cooking, and when you decide to get an electric vehicle (EV). In addition, EVs are the way to go in the future.

graph on EV projection until 2030
Projection by Prof. Ray Wills, 

The graph above shows the global projection of EV sales. Prof. Ray Wills predicts that in just 4 years, EVs will increase their market share from just 16.6% to 100%! We reckon that Australia will follow this trend and take up EVs in a very similar fashion.

The Solar Analytics customers who have already got an EV all maximise their use of their own rooftop solar generation because it is the cheapest electricity available. In fact, to drive 100km in a Tesla Model 3 charged from your own solar will cost you about $1.60, compared to $17 for a Toyota Camry at today’s exorbitant fuel prices.

What size solar system do I need for my house?

Another important thing to consider is energy storage. The price of batteries is high right now, but as prices come down and you begin to think about getting one, you'll want to maximise the use of your battery with a larger solar system. A larger solar system will allow you to store more electricity for later use, even on cloudy days, which will increase your savings.

Should you install a small system and upgrade later? We recommend that you install the biggest system possible from the start. You can always add on later, but it's not ideal and will cost you more in the long run. 

Our CEO Stefan Jarnason has always been a visionary. After twenty years of painstakingly designing the optimal size rooftop solar systems for homes, because solar panels are so cheap the best size solar system is simply the biggest one they can fit on their roof. The bigger the better, North, East, West and even South as long as the roof is not always in shade (some shade is fine).

How many kW of solar power do I need?

Despite this Stefan fell into the ‘too small system trap’. Three years ago, having just moved homes, Stefan installed a solar system on his new roof. Initially opting for a 6.6kW system, he later realised it was too modest. Determined to reduce his bills and accommodate a newly installed swimming pool, Stefan convinced his solar retailer to expand the system to 8.5kW, albeit with all the additional panels on the east-facing roof, which received some shade.

Fast forward to two years and guess what - the system is way too small because he wanted lower bills and had just installed a swimming pool. Doh! In response, Stefan added another 8kW of solar panels, oriented to the west (with some shade) bringing his total to a robust 16kW system. Despite his 5kW export limit, this extra 8kW is still providing a good financial return.

But Stefan’s decision to upgrade later instead of doing it from the start meant he needed to spend an extra $1,800 for the hardware and installation over getting a 16kW system in the first place. Even now, he’s thinking he should have squeezed in another 8kW for he gets another EV and switches to an induction cooktop!

Is now the right time? Absolutely!

With over 3 million Australians already enjoying low energy bills thanks to rooftop solar, there has never been a better time to go solar. Although it might seem like a lot of money to pay for an investment that you can't see, it is possibly the best financial investment you will make after your home. The cost of a solar system has dropped dramatically over the past decade, but prices have now stabilised (in part due to the government STC rebates falling by 5% pa until 2030). If you’re interested, a recent article shows the potential for solar in the near future.

graph in the decreasing cost of solar panels
The price of solar systems has dropped significantly in the past decade

We recommend you take a look at the rebates from the Australian Government and take advantage of them! You should also contact your bank to see what amazing loans they have for solar — for example check out how CommBank offers 0.99% for 10 years here.

When you're thinking about installing solar panels, there's a part of you that might think, "It'll be nice to wait a few years and see if the technology improves or prices go down." While it is true that prices have been dropping and the efficiency of panels has been going up, it's more important to remember that every day you don't install solar is another day you're paying for electricity that could have been free.

Waiting longer to get solar and switch electricity providers means you are paying too much for electricity and being held hostage by your power company. If you install as many panels as possible now and take advantage of what is currently available, you could save thousands over the course of your lifetime. What are you waiting for? Get a quote from your solar retailer and make sure to include Solar Analytics advanced monitoring so you’re always on top of your solar!

Energy prices are increasing, and increasingly confusing

Energy prices across Australia have increased in recent times and are projected to continue rising in the near future. It’s an excellent opportunity to switch to solar and install as much as possible to combat the price hikes. In the long term, we don't know how much electricity prices will rise and how frequently they change. The uncertainty is such that even the Reserve Bank of Australia has an article explaining how a combination of factors caused the sharp increase in electricity prices.

man confused looking at laptop screen

It’s hard to predict the right energy retailer because they have various feed-in tariffs and variable rates depending on the time of use, and the next thing you know, prices are going up again. Canstar Blue compiled a series of monthly changes by energy providers and it’s staggering how much the plans change every single month! It is likely that energy retailers are deliberately trying to confuse you with the complexity and uncertainty just so you pay the “lazy tax” and not shop around for the best plan!

The solution? Cover your roof with as many solar panels! We discussed earlier how having larger solar systems will give you energy freedom. Imagine the freedom you get by not having to worry about energy bills or price changes. That is the energy freedom you get with large solar systems.

And to make sure you have the best energy plan for you, there are tools out there such as Solar Analytics’ Plan Comparison Tool which will do all the work for you.

More solar, more savings, more freedom!

Let’s remind ourselves of the main goal of installing more solar: energy freedom. We want the freedom of having near-zero power bills. We want freedom by not having to worry about energy price changes and their uncertainties. Lastly, we also want the freedom of having a net carbon-zero emissions home, and ideally having someone else automatically ensure we are on the best energy deal.

What’s the best, most cost-effective, way to do it? Cover your entire roof with solar panels. It is as simple as that. The bigger the solar system, the higher the savings, and the more freedom there is!

If you have ever installed a solar system on your roof, you know that it is a great choice. When we surveyed our customers, none of them wished for a smaller system, while many like our CEO Stefan were already wishing they put in a larger system. Get a quote from your solar retailer and make sure to include Solar Analytics today!

Key Takeaways

  1. Cover your roof with solar! The more panels you have, the better
  2. Get solar today. Now is the best time to install a solar system for your home
  3. Get advanced monitoring to optimise your energy plans, solar performance, and are always on top of your electricity consumption.