Updated on October 20, 2025
With over 30% of Australian homes covered in solar panels, buying a home with a previously installed system is becoming more and more normal. But not every solar system is the same. Some systems last decades and others don’t. Which type of solar system are you inheriting when you purchase a home with solar included?
It can be difficult to know what questions to ask about the existing solar system.
At PSC Energy, our goal is to help you understand every aspect of the solar industry so you can be informed as we work together to reach Net Zero by 2050. We also want to help you save a bit of money on your electricity bills as well.
In this article, you will learn about why you must ask the following questions:
- Who Installed the Solar Panel System?
- What Type of Solar Panel System is It?
- When Was the Solar Panel System Installed?
- Are the Warranties for Your Solar Panel System Transferrable?
- How Many Kilowatts Does Your Solar Panel System Produce?
- Considerations About Solar Batteries
- FAQ: Buying a House with Solar Panels
By the end of this article, you’ll know what to look out for when purchasing a home with solar already installed.
Who Installed the Solar Panel System?
This is the most important component of any solar system installation. When you’re dealing with an existing solar system, it’s even more crucial. A poorly installed solar system can be unreliable, under-performing, and sometimes even unsafe.
In order to be able to install solar systems in Australia, an electrician must be certified by the Solar Accreditation Australia (SAA).
From there, an electrician can either work for an in-house solar installer like PSC Energy or hang up a shingle for a solar sales company and work for them (or multiple solar sales companies) as a subcontractor.
An in-house installer is a full-service, inquiry to installation solar systems service. An in-house installer will quote you based on your needs, install the solar system, and cover all warranties on your behalf. PSC Energy also has an additional workmanship warranty.
All warranties for installations with PSC Energy are transferrable from one owner to the next.
A subcontractor working for a solar sales company is a different business model. In this installation practice, a solar sales company will work with you to determine your solar needs. Then they will hire a subcontractor to install the system.
This is a very common type of installation in Australia, especially because of the popularity of string inverter systems (we’ll get to those in a bit).
Subcontractors are popular because of how economical their installations are for customers. However, the process of getting warranties fulfilled can be complex and time consuming.
When purchasing a home with solar, you’ll want to learn whether the installation was done by an in-house team or a subcontractor. If it’s an in-house team, there’s a very good chance that they will assist with the transfer of the system and the warranties (if they’re still in effect).
If the solar system was installed by a subcontractor, you’ll need to find out if they are responsible for any existing warranties or if the solar sales company will fulfil them.
Often, there’s a disconnect between the subcontractor and the sales company with neither of them taking responsibility for repairing the system. This can lead to a very frustrating round-robin of phone calls and delays in getting your system up and running again if it requires repairs of any kind.
If you’re interested in learning more about the differences between in-house installers and subcontractors, you might want to check out the following article titled, In-house Installers vs. Subcontractors: Which is Better?
What Type of Solar Panel System Is It?
You’ll need to determine what type of solar system the house has installed on it. As previously stated, not all solar systems are created equal. Does the solar system have microinverters or a central (string) inverter?
Inverters are one of the most important components of your solar system. Determining what type of inverter you have will inform every other choice you make regarding your solar. It’s actually more important than the panels up on the roof.
Microinverters and string inverters serve the same purpose in a solar system: They convert the power harvested by the solar panels into usable electricity for powering the home.
Solar panels output direct current (DC) electricity, but the lights and appliances in residences run on alternating current (AC) electricity. The conversion process that microinverters and string inverters do is necessary to make solar power usable.
The importance of knowing whether it’s a microinverter or string inverter system will inform the choices you make in the repair and expansion of the system.
Repairs: Microinverters are warrantied for 25 years. There is the possibility that a microinverter could fail early in its life cycle, but this is an exception that proves the rule.
A string inverter will need to be replaced years before a microinverter. String inverters are often warrantied for 5 – 10 years depending on the manufacturer. It’s the workhorse of the system and will need to be replaced years before the solar panels.
Expansion: Because of the decentralised design of a microinverter and the ease of using the plug-and-play engineering of this technology, microinverters solar systems are easy to expand and upgrade if your solar needs are greater than the previous owner or if they change in the future.
The design of string inverter systems makes it difficult to expand an existing string system in the future. Oftentimes, a string system will need to be fully replaced if you decide to expand it in the future.
You may or may not want to do this. Evaluating your energy needs and whether they change in the coming years will determine if you’ll want to do this.
If you’re interested in learning a bit more about solar panels and energy systems, you might want to check out the following article titled, Are Solar Panels Worth It in NSW, Australia? A Price Breakdown for 2025.
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When Was the Solar Panel System Installed?
Remember when we said that 30% of Australian homes have solar? We’ve been doing it as a country since the early 2000s. In the decade between 2010 and 2020, most Australian solar systems went up on roofs nationwide. Solar has really taken off here, and why wouldn’t it? There’s so much sunshine.
However, solar system technology has grown by leaps and bounds over the years. The house you want to purchase might have an inefficient system on it if it’s older. If it’s less than 5kW output or if the solar panels output less than 200W, then that system is out of date and may struggle to keep up with your energy needs.
It doesn’t mean it’s a dud, it just means that you might need to upgrade your system at some point. Plenty of 5kW systems are fully capable of cutting down those energy bills. With the cost of electricity continuing to rise, however, you shouldn’t expect to see the same energy savings that a newer system provides.
When considering the age of the system, you’ll want to understand what type of equipment you might need to replace. Some equipment in solar systems is only compatible with specific brands.
You’ll want to investigate whether the company that manufactured the system components is still in existence and whether you’re able to find replacement parts should you need them.
If you’re interested in learning a bit more about weighing the cost of solar against the cost of the grid, you might want to check out the following article titled, Cost of Solar Panels vs. Cost of Energy from the Grid.
Ready to go solar? Click here.
Are the Warranties for Your Solar Panel System Transferable?
Warranties and paperwork for those warranties are really important. Most equipment warranties for solar systems are transferable, but you’ll need to confirm to make sure that the solar panels, inverter, and workmanship warranties can be handed over to you.
Subcontractors and solar sales companies come and go and have come and gone. It’s not unusual for a solar system to outlive the company that sold or installed it for the previous owner. Check to make sure they’re still in business.
At PSC Energy, we transfer manufacturing warranties to the new owner and stand behind our workmanship warranty regardless of who owns the home. But we do require the new owner to work with us and provide whatever documentation they received from the previous owner.
Make certain to collect this paperwork if you’re able to. It will accelerate the process of getting your solar warranties fulfilled.
For more information on warranties, you might want to check out the following article titled, A Complete Guide to Solar Warranties.
How Many Kilowatts Does Your Solar Panel System Produce?
This question is about how much energy you can expect from your system. How much electricity will you get from the solar panels up on the roof?
A 6.6kW system, which has been a popular system size in Australia for years, will produce over 26kWh of daily electricity to use.
An average family of four can generally estimate between 18 – 25kWh of daily electricity use. It’s a wide range because there are factors like location, time of season, and unique energy consumption needs.
Not to mention the rising cost of electricity nationwide. The savings could be significant: the 6.6kW system we used as an example could generate up to $40 – 50,000 worth of savings in electricity for the lifespan of the system.
Larger systems are becoming more popular as Australians confront energy bill increases. The future of solar energy is evolving very rapidly as well. Electric vehicles and the need to charge them and integrated smart home technologies will change how much electricity a family of four might need.
There are a variety of factors that will influence how much electricity that hypothetical family of four will need and how much money a solar system might save them.
Your best bet is to consult a reputable solar installer for specifics about what your energy needs might be. There are external factors that will influence this. These estimates are based on the current cost of electricity and that cost will certainly rise.
If you’re interested in learning a bit more about the price of solar batteries, you might want to check out the following article titled, How Much Are Solar Batteries? A Full Breakdown of Prices, Rebates, and Value in 2025.
Ready to go solar? Click here.
Considerations About Solar Batteries
Solar batteries are becoming more and more common in households in recent years. They’ve developed very rapidly to become a smart investment rather than a luxury item.
If the previous owner installed a solar battery in the home you’re about to purchase, you’ll need to know how old the battery is and how many cycles it has gone through.
A cycle is how many times a solar battery fully charges to capacity and discharges all the energy stored within. The size of the battery and how much electricity the home consumes will determine how often it cycles.
It’s normal for a battery to degrade during its lifetime. This is just the scientific reality of solar batteries. Over time, the battery will lose the capacity to store as much energy as it did when it was initially purchased.
Warranties for solar batteries often have an either/or option for when they expire: a number of years or a number of cycles. For instance, the Enphase IQ Battery 5P has a warranty that covers 15 years or 6,000 cycles, whichever comes first.
As we explained above, it’s crucial to get the correct information from the previous owner to ensure that the warranty is transferrable and covers the rest of the battery’s lifecycle.
If you’d like to learn a bit more about what solar batteries are on the market, you might want to check out the following article titled, 6 Best Solar Batteries on the Market.
Is It Worth Buying a Home with Solar?
Absolutely, yes!
You will not have spent any money on the installation of the solar system, and your electricity bills will be reduced or eliminated depending on the solar system you inherit.
You’ll want to ask the discussed questions to determine whether you’ll need to spend money replacing the system or any of its components. You’ll also want to have the correct information and documentation for any warranties that will potentially require fulfilment down the road. What type of system you’ll inherit and who installed it are also key components when it comes to upgrading the system in the future.
There are so many advantages to installing a solar system, but having it already installed is a modest but beneficial winning lottery ticket.
At PSC Energy, we’re focused on helping you get the most out of your solar journey. The research you do today will inform the choices you make years, if not decades, in the future. Whether you’re buying a new system or moving into a residence with an existing system, you’ll need to know its abilities and limitations.
If you’re interested in learning a bit more about expanding your energy system, you might want to check out the following article titled, Expanding Your Solar Panel System with Batteries and Add-Ons.
FAQ: Buying a House with Solar Panels
What should I ask the seller about the solar panel system before I buy a house?
Ask who installed it, what model the inverter is, what brand the panels are, and whether a battery is attached. Ask when the system was installed and the system size in kilowatts. Ask if the installer was an in-house team or a subcontractor. Ask for all paperwork, including invoices, single line diagrams, product datasheets, and warranty certificates. Ask for the monitoring login so you can see performance data.
How do I tell if the installer was an in-house team or a subcontractor?
Check the invoice and warranty papers. An in-house installer lists one company for sales, install, and workmanship warranty. A subcontracted job often lists a sales company and a different electrical contractor for the install. You can also call the company on the paperwork and ask who handles warranty claims.
Why does the original installer matter so much?
The installer controls workmanship quality and warranty support. A good in-house installer handles design, install, commissioning, and future service. Subcontracted systems can create confusion during faults because the seller and installer may pass responsibility. Clear responsibility saves time and money when you need help.
What type of solar panel system is on the roof: microinverter or string inverter?
Look at the inverter hardware. A string inverter is a single box on a wall near your switchboard. A microinverter system has a small inverter under each panel and often a small gateway inside. You can also check the monitoring app or the invoice. Knowing the type helps you plan repairs, upgrades, and expansion.
How do microinverters and string inverters differ for a buyer?
Microinverters convert DC to AC at each panel and usually carry 25-year warranties. They handle shade better and are easy to expand later. String inverters convert power in one central box. They are less expensive upfront but usually have 5 to 10-year warranties and need replacement earlier. Expansion is harder on string systems.
How old is too old for a solar system?
Age is a clue, not a verdict. Many systems from 2010 to 2020 still run well. If panels are below about 200W each or the total system is under 5 kW, the system may struggle with today’s bills. Very old brands may be discontinued, which makes parts hard to source. Plan for upgrades if output and parts availability are limited.
What documents should I collect at purchase or settlement?
Collect the original quote and invoice, Certificates of Compliance, product serial numbers, warranty certificates, network approval, and the monitoring login transfer. Ask for the solar design or single line diagram. Keep photos of the array layout and the location of isolators and breakers.
Are the solar warranties transferable to me as the new owner?
Most equipment warranties are transferable, but you must read the fine print and follow the brand’s process. Workmanship warranties depend on the original installer. Contact the installer to confirm transfer and required proof of ownership. Keep all paperwork. It speeds up any future claim.
What is the expected daily output and how do I check it?
As a guide, a 6.6 kW system can produce over 26 kWh per day on average across the year. Compare this with your bill and usage. A family of four often uses 18 to 25 kWh per day. Use the monitoring app to check real output. Confirm that the system’s production matches the expected range for its size and location.
Will the existing solar panels save me money?
Yes, if the system is healthy and sized well for your usage. Daytime use should come from solar first. Any extra energy offsets evening use if a battery is present. Without a battery, excess exports earn a small feed-in credit. Larger, newer systems and homes that shift usage to daylight hours see the biggest savings.
Can I expand the solar panel system later?
Usually yes with microinverters. Expansion is simple because each panel has its own inverter. Expansion on string systems is hard because strings must match and the central inverter has fixed capacity. Many older string systems need a full redesign or a new inverter to expand. Ask an installer to check capacity and roof space.
What should I know about the solar inverter’s lifespan and replacement costs?
String inverters often need replacement within 5 to 10 years. Budget for that if the system is older. Microinverters are designed to last longer and are replaced module by module if one fails. Knowing the inverter age helps you plan future costs and avoid surprise downtime.
The house has a solar battery. How do I assess its condition?
Find the brand, model, install date, and cycle count. A cycle is one full charge and discharge. Batteries lose capacity slowly over time. Check the warranty terms for years and maximum cycles. Confirm the warranty transfer steps. Use the monitoring app or installer report to check present capacity and recent error logs.
How long do solar batteries last and what are typical warranties?
Most modern home batteries last 10 to 15 years. Many warranties are written as the earlier of a set number of years or cycles. For example, 15 years or 6,000 cycles. Read the warranty for throughput limits and required operating settings. Keep the battery well-ventilated and within its temperature range.
Can I go fully off grid with the existing solar energy system?
Most systems in NSW remain grid connected. Off grid requires a large battery and a system designed for full backup, often with a generator. A standard grid system with a battery can still give strong blackout protection. Check your system specs before assuming off-grid capability.
Do I get any rebates for a solar panel system that is already installed?
No for the original panel rebate. The federal STC incentive is claimed at the time of installation. You cannot claim it again. Battery and other incentives only apply when you install new eligible equipment. If you add a new battery after purchase, you may qualify under the current rules.
What should I check on the switchboard and roof for safety?
Make sure labels are clear, isolators are intact, and breakers match the paperwork. Look for damaged conduits, loose cables, cracked tiles, or signs of water ingress. Check that rooftop isolators are sealed and secure where present. If anything looks wrong, book a licensed solar electrician to inspect before settlement.
How do I take over the solar monitoring app and data?
Ask the seller to transfer system ownership inside the app or provide a change-of-owner form. Update the gateway’s Wi-Fi to your home network. Confirm that production, consumption, and battery data are flowing. Save all login details and support contacts.
What are my first steps after I move in?
Record serial numbers and take photos of the inverter, battery, and switchboard. Change the monitoring login and Wi-Fi details. Read the most recent performance graphs. Book a health check with a reputable installer if the system is older, has no paperwork, or shows errors. Put warranty and service contacts in one folder.
When should I consider upgrading or adding a solar battery?
Consider upgrades if bills stay high, the inverter is near end of life, parts are obsolete, or your usage has grown. Add a battery if you use more power at night, want blackout protection, or plan to charge an EV. A right-sized battery can lift self-consumption and shorten payback.
Is buying a home with solar panels worth it?
Yes. You avoid the upfront install cost and start with lower bills on day one. Make sure the system is healthy, the warranties transfer, and the paperwork is complete. A simple inspection and clean handover protect your investment and keep the savings on track.
