A solar system on a house you are buying can take a real bite out of your future power bills, but only if it works, is compliant and comes with the paperwork you need. Before settlement, find out how old the system is, what equipment it uses, whether warranties are still in force, how you will access the monitoring and what condition the inverter and any battery are in. A standard building inspection does not usually test solar in detail, so plan a separate check.

Start with the system's age and components

Ask the selling agent for the installation date and the make, model and quantity of the panels, inverter and any battery. The inverter label, the electrical compliance certificate or the original invoice usually shows these. Age tells you a lot:

• Panels commonly lose around 0.4-0.55% of their output a year, so a well-made ten-year-old array still produces most of its original rating.
• Inverters are the component most likely to need replacing during a system's life; many last around 10-15 years, and their warranties are commonly much shorter than panel warranties.
• Older systems may be small, such as 1.5 kW or 3 kW, and use panels that are no longer made, which limits future expansion.

Look up the panel and inverter brands. Established manufacturers with an Australian presence make warranty claims and replacement parts far simpler; our panel brands comparison explains what to look for.

Paperwork to request before settlement

Ask your conveyancer or solicitor to confirm that the solar system, battery and any EV charger are included in the sale, and that the documents will be handed over at settlement.

Warranties: what transfers and what does not

Manufacturer product and performance warranties generally stay with the equipment, but some depend on the warranty having been registered, and nearly all require proof of purchase and the installation date. Workmanship warranties come from the installer and vary: some transfer to a new owner, some do not, and they are much harder to use if the installing business has closed. Contact the installer and manufacturers named on the paperwork to ask how a change of ownership is handled. Our solar panel warranty guide explains the difference between product, performance and workmanship cover.

Monitoring access and electricity accounts

Monitoring apps are usually registered to the seller's account. Without access, you cannot see whether the system is producing or receive fault alerts. Ask the vendor to transfer the monitoring account or release the inverter so it can be registered to you after settlement. If the monitoring gateway is missing or offline, note that in your negotiations.

Feed-in tariffs belong to the seller's electricity contract, not to the house. You will choose your own retailer and plan after settlement, so compare offers based on your expected usage and export rather than assuming the seller's rates carry over.

Checking the inverter, panels and battery

During your inspection, you can look safely without touching anything electrical:

• Does the inverter display or status light show normal operation, or an error or fault message?
• Is the inverter in full afternoon sun, or showing heat discolouration, rust or insect nests?
• From the ground, are any panels visibly cracked, discoloured or heavily soiled?
• Are there water stains on ceilings below the array that could point to a roof leak?
• Is any battery in a location that is clear of clutter and out of direct sun?
• If there is a battery, is it enrolled in a VPP, and does that agreement end with the sale?

Do not open isolators, switchboards or inverter covers, and do not climb onto the roof. A licensed electrician or accredited solar professional can test the system properly, and many vendors will allow a separate inspection before exchange.

Questions to put to the vendor

The selling agent may not know the answers straight away, so send these questions in writing early in the process:

1. When was the system installed, and by which company?
2. Has the inverter ever been replaced or repaired, and are there service records?
3. What did the last twelve months of electricity bills look like, including exports?
4. Have there been any roof leaks, storm damage or insurance claims involving the panels?
5. Is the battery or any other equipment financed, leased or subject to an ongoing agreement?
6. Will monitoring logins, manuals and spare parts, such as a monitoring gateway, be left at the property?

Written answers help your conveyancer and give you a record if something turns out to be different after settlement.

Putting a value on the system

An existing system is not worth what it cost new. A small, older system with an inverter near the end of its life may need money spent within a few years, while a recent, well-documented system with a battery can add genuine value. For context, a new 6.6 kW system in Sydney is indicatively $4,500-$6,500 after STCs in 2026, and a 10 kWh battery $8,000-$11,000 after the federal battery discount, both confirmed after a site assessment. Use those figures to sense-check any claim about what the solar adds to the price, and see our maintenance checklist for the upkeep to expect once you move in.

Next steps

Request the documents early, ideally before exchange, and arrange a professional inspection if the system is more than a few years old or the paperwork is incomplete. An Electrical Safety Inspection, where a licensed electrician tests the solar isolators, earthing, insulation resistance and safety switches, is listed at $299 in the energy market, an indicative price. If you plan to upgrade the system or add a battery after you move in, request a free assessment from Blue Energy Solar.

Frequently asked questions

Does solar increase the value of a house?

It can, particularly when the system is recent, well documented and paired with a battery, because buyers see lower running costs. The effect varies with the property, the local market and the system's condition, so there is no reliable fixed figure. A valuer or local agent can advise on your area, and the system's paperwork and production history help support any value placed on it.

Can I ask the vendor to fix a faulty solar system before settlement?

You can ask, and whether they agree depends on your negotiation and the contract. If an inspection finds a fault, get a written report and a repair estimate, then discuss the options with your conveyancer or solicitor: a repair before settlement, a price adjustment or accepting the system as it is. Make sure any agreed repair is carried out by a licensed professional and documented.

What if there is no paperwork for the solar system at all?

Missing paperwork does not always mean a problem, but it makes warranty claims harder and leaves compliance unconfirmed. The inverter and panel labels still identify the equipment, and the vendor may be able to request copies from the original installer. Treat an undocumented system cautiously when weighing up the price, and have a licensed electrician inspect it before you rely on it.