7 Things To Consider When Adding Solar Panels To An Existing System

Feature image for the "adding solar panels to an existing system" article. Image shows solar installers collaborating on top of a rooftop.

According to the Australian government, there have been over 3 million rooftop solar systems installed on homes around the country since 2022. You’re probably one of these homeowners, you’re satisfied, and you’re now considering adding solar panels to your existing system. 

But before taking the plunge and investing in new solar panels, there are a few things that you should consider to maximize your investment and really reduce your electricity bills.

These include your roof space, energy needs, the type of existing system you have, whether it’s even possible or a good idea, and other things. 

I will explain these considerations in the article below. I will also discuss other related topics. If you want to read ahead, simply tap on the bullet points below, but I recommend reading this from the top. Let’s go! 

Can I add solar panels to my existing system?

The straightforward answer to this question is yes, you can add solar panels to your existing system. 

However, depending on a few factors (discussed below), the process might not be as simple as bolting new panels to your roof. The truth is that it might not even be cost-effective. 

That being said, consider these factors before you upscale your system. 

7 factors you should consider before you add more solar panels to your home

Infographic outlining the 7 things people should consider before adding solar panels to their existing solar systems

1. The age of your existing solar panel system

A solar system installed between 2007 and 2012 is generally safe to upgrade with additional panels. However, you would also need solar panels from the same generation, and that’s way harder than it sounds.

Technology has progressed so far since then, so adding modern solar panels to an existing system with older panels isn’t practical. 

For one, the newer panels will need their own system, so you’re going to need new inverters, cables, charge inverters, and other things. Second, the cost of installation is also going to cost you more because they might not be covered by Australia’s rebates

2. Your inverter’s capacity

Ensure that your inverter has the ability to handle the additional power being generated.

If you want to add more panels to your system without spending too much money, you should also check if your inverter’s capacity is capable of supporting the added power. 

That being said, it’s always a good idea to evaluate how much power your existing panels are producing, how much you’re consuming, and how much more you can add that your solar inverter can also handle. 

For further reading: What size inverter does your home need?

3. Are your new solar panels compatible with your existing solar inverter? 

You also need to ensure that your additional solar panels are compatible with the current solar system and inverter you have installed. 

If not, you can either change your new solar panels to another compatible one, change your inverter to one that’s compatible with the old and new panels, or add another inverter to your system. Naturally, that last option is going to be the most pricey. 

Recommended: The 4 types of inverters you can have on your home.

4. Installation requirements

The Australian government has set standards for installing solar systems in homes to help ensure that they’re practical, safe, and durable. Hence, you should only hire a solar company that has CEC-accredited installers to help you. Trust me, they can save you so much trouble in the future.

Also, you should have a look at local building regulations and acquire the necessary permits and approvals that you need. 

5. Roof space and structure

Other things to consider before adding solar panels are your roof’s structure and space. Your roof should be sturdy enough to hold the weight of your new solar panels plus the weight of the original. 

You should also have enough space on your roof to install the new solar panels. If not, you will need to consider other places to mount your PV panels, such as the ground or maybe even your garage’s roof. 

For further reading:

6. Your system’s size

Another important factor you need to keep in mind is the size of your existing solar PV system. 

For your system to still be eligible for Australia’s rebates, your panels’ capacity must not be more than 100 kW. For most Australian homes, 6.6 kW is sufficient anyway, so the government does give you a huge leeway. Still, it’s something worth considering. 

Moreover, check with your energy provider to see if they also have limits.

7. Solar battery storage

Lastly, you might want to consider adding solar battery storage to your existing system. More panels mean more power. Having a battery makes it possible to store—and therefore use—all of the electricity your system generates. 

But if you already have a battery inverter, you should also check if its capacity can store the additional power from your new solar panels. 

How to add more solar panels to your existing system

Infographic explaining 3 ways to add more solar panels to existing systems.

If you have evaluated all of the necessary factors and decided to move forward with adding additional solar panels, here are 3 ways you can go about it: 

Keep the old inverter and add more panels to the existing system.

Option one offers the most accessible solution among all of these alternatives. With this approach, you can keep your older inverter, which means you also save more money. 

But, again, this relatively inexpensive option also requires that your old inverter be compatible with your new solar panels and capable of handling the added power. 

Install a new inverter with more panels connected to it.

Buying a new inverter will get you either of 2 things. 

One, your new inverter can support the new solar panels in case the older one isn’t capable or compatible. Or, two, the new inverter can support both the older and newer panels. 

Either way, you’re going to end up spending more money with this option compared to the last one. 

Install additional solar batteries along with the existing ones.

As I’ve said, solar batteries can store the excess energy in your solar power system that you don’t use during the day. This makes you less reliant on the grid because you’re able to use solar power even at night. 

Now, when you’re installing more panels in your system, you’re also going to be generating more power. So, aside from inverters and solar panels, consider upgrading your battery or adding one if you haven’t already. 


Can I have two solar systems?

Yes, you can install two solar systems. However, be aware that this likely also means a higher installation cost. 
Recommended: Solar panels on both sides of your roof: Yay or nay?

How many solar panels can my inverter handle?

The number of solar panels your inverter can handle depends on both of their capacities. According to the Clean Energy Council, your solar panels’ capacity can only exceed your inverter’s capacity by 33%.


Upgrading an existing solar panel array in order to produce more energy with additional panels is undoubtedly possible. Though it requires careful consideration of various factors to ensure a safe and efficient installation.

To avoid any complications, it’s best to consult a solar installation expert or licensed solar technician before taking any steps.

If you need help looking for these people, we have a network of pre-vetted installers that you can use. We can get you 3 FREE quotes right now.