10 solar mistakes that cost Australians money

Buying solar is a big upfront expense, so getting the wrong system can be an expensive mistake.

And it's not always obvious where things can go wrong. A cheap quote, the wrong system size or a battery you don't really need can all affect how much you save.

Here are 10 common solar mistakes to look out for before you buy.

1. Choosing on price alone

The cheapest quote can be tempting, but it may not be the best option in the long run.

A lower price might mean cheaper panels or an inverter that's not well matched to the system.

It could also mean you're dealing with an installer that's harder to reach if something goes wrong later.

When comparing quotes, check the panel and inverter brands and models, warranties, who's doing the installation and whether they're an accredited solar installer (we'll discuss this in more detail further down).

Getting three quotes can make these differences much easier to spot. And if one is thousands of dollars cheaper than the others, find out exactly what's included before you sign.

2. Sizing your system around your daytime usage

It's easy to look at your annual electricity use and size your solar system around that number.

But that doesn't tell you when you're using the most power.

What matters is how much electricity you use while the sun is shining, because that's when your solar can directly power your home.

If you're out all day and use most of your electricity at night, a large solar system could leave you with more excess power going to the grid.

Check your 12 months of interval data from your retailer or smart meter to see when you're actually using electricity, not just how much you use.

Then talk to your installer about a system that matches your daytime usage, with room to account for things like a future battery, EV or heat pump.

3. Expecting the feed-in tariff to pay for the system

This is the single most expensive assumption in solar right now.

Australia has more than 4.2 million rooftop PV installations, and they all generate at once. That floods the grid in the middle of the day, pushes wholesale prices down, and drags feed-in tariffs with it.

Rates that were 15c to 20c a few years ago are mostly 3c to 10c in 2026.

Think of your feed-in tariff as a nice extra, not the main reason you're getting solar.

And don't pick an energy plan just because it has a high feed-in tariff. You could end up paying more for your electricity or daily supply charge, which can wipe out those extra feed-in credits. Compare the whole plan, not just the feed-in rate.

4. Not checking your installer is accredited

Choosing the wrong installer could mean missing out on government rebates and leave you with fewer protections if something goes wrong.

For the federal solar rebate, your system needs to be designed and installed by an appropriately accredited installer so you can claim Small-scale Technology Certificates (STCs).

Before you sign, check that your installer is accredited by Solar Accreditation Australia (SAA).

You might still come across older guides telling you to look for a "CEC accredited installer".

Installer accreditation moved from the Clean Energy Council to SAA, so SAA is the name to look for now.

It's also worth checking whether the retailer is signed up to the New Energy Tech Consumer Code (NETCC).

It covers things like sales, contracts, finance and complaints.

Just keep in mind that installer accreditation and product approval are different things. The Clean Energy Council still maintains the approved product lists used for some government incentives, including battery rebates.

5. Signing on the spot

You don't need to sign a solar contract just because a salesperson tells you the deal won't be around for long.

Some government incentives do have scheduled changes, but that doesn't mean you need to rush into a five-figure purchase without comparing your options.

Take the quote home and give yourself time to check the panel and inverter models, read the contract and compare it with a couple of other quotes. It's also worth checking the company's reviews and how long it has been operating.

If you're approached through an unsolicited door-to-door sale, you may also have cooling-off rights under Australian Consumer Law. But the easiest way to avoid a rushed decision is to simply give yourself time before signing.

6. Ignoring what your roof can actually do

Your roof can make a big difference to how much electricity your solar system produces, so don't rely on a quote based only on your address or a quick phone call.

Things like shade from trees, chimneys and other buildings can reduce the amount of solar you generate.

The direction and angle of your roof matter too.

North-facing panels generally produce more over the course of the day, while east- and west-facing panels can shift more generation into the morning or afternoon.

Your roof itself is worth checking before you install anything. If it's likely to need replacing in the next few years, it may be cheaper and easier to sort that out first rather than pay to remove and reinstall your panels later.

Ask for a site inspection or a detailed shading assessment, and check what assumptions the installer's estimated annual output is based on.

7. Not checking your network's export rules

Before you choose your system, check how much solar your local electricity network will actually let you export.

Your distributor sets the export limit, not your electricity retailer.

Depending on where you live, you may not be able to send all of your excess solar back to the grid, even if your panels are capable of producing it.

Some networks are also changing how they charge for and reward solar exports, including lower or even negative rates for some daytime exports and incentives for exporting at other times.

That doesn't mean you need to avoid a bigger system.

It just means you should know your local export rules before you pay for more panels, and ask your installer how those limits could affect your system.

8. Misreading the warranty

Seeing "25-year warranty" on a solar quote doesn't necessarily mean everything is covered for 25 years.

There are usually a few different warranties to look at

• Performance warranty covers how much electricity the panels are expected to produce over time. This is often the 25-year warranty you see advertised.
• Product warranty covers faults with the panels themselves and is often shorter.
• Workmanship warranty covers the installation, including things like mounting and wiring, and is set by the installer.

The inverter has its own coverage too, which is often shorter than the panels.

When you're comparing quotes, check what you're actually covered for, including labour, removal, shipping and replacement costs.

And make sure you know who you'll need to contact if something goes wrong down the track.

9. Adding a battery without doing the maths

A battery can make sense, especially with the federal Cheaper Home Batteries Program reducing the upfront cost of eligible systems.

But a rebate doesn't automatically make a battery worthwhile for every home.

How quickly it pays for itself depends on things like your electricity use, when you use the most power, your feed-in tariff and whether you can make money from a virtual power plant.

If you're already using most of your solar during the day, there may not be much excess left to store.

On the other hand, if you're regularly sending lots of solar back to the grid and using plenty of electricity at night, a battery could help you get more value from your system.

There are a couple of other things to keep in mind.

A battery won't necessarily keep your lights on during a blackout. You'll need a system that's set up for backup power. And bigger isn't always better. There's little point paying for more storage than you can regularly fill and use.

If you're thinking about adding one to an existing solar system, see our guide to adding a battery to an existing solar system.

You can also compare home battery prices and capacities before making a decision.

For more on backup power, see whether solar panels work during a power outage.

10. Not checking the cost of solar finance

You can choose the right solar system and still lose some of the savings if you pay for it with expensive finance.

Putting $12,000 of solar on a credit card charging around 20% p.a. could add thousands of dollars in interest, eating into the savings your system makes.

At the other end, a 0% interest payment plan isn't necessarily free either. Account-keeping and establishment fees can add up over the life of the loan, so make sure you know the total cost before you sign up.

The simplest way to compare your options is to look at how much the system could save you each year and how much your finance will cost.

If the finance costs more than you're saving, you may want to look at a smaller system, a different finance option or waiting until you can pay for more of it upfront.

Make sure the amount you're borrowing reflects any rebates or discounts that have already been taken off the system price.

You can also compare the installer's finance option with a green personal loan or any state government low-interest loan you're eligible for, as these may work out cheaper.

How these mistakes can affect your savings

The exact impact depends on your system, your electricity use and where you live. Here's what can happen if you get these decisions wrong.

Before you sign, run this checklist

• You have three written quotes and have compared the panel, inverter and warranty details line by line.
• You have looked at 12 months of interval data and know when you use the most electricity during the day.
• The installer is accredited by Solar Accreditation Australia and you have checked their accreditation.
• You have confirmed your distributor's export limit for your address.
• The quote shows the price after rebates and you know exactly how much you're financing.
• If a battery is included, you know whether it provides blackout backup and how it could affect your bills.
• You have compared the installer's finance offer with at least one outside option.

Frequently asked questions

• Is solar still worth it in Australia in 2026?

  For most households with reasonable daytime usage, yes.

  What has changed is where the return comes from. With feed-in tariffs mostly between 3c and 10c per kWh, the savings now come from using your own generation rather than exporting it.

  That makes system sizing and your usage pattern far more important to the outcome than they were when export rates were high.

• What size solar system should I get?

  There is no standard answer, because it depends on how much power you use during daylight hours rather than how big your bill is.

  Pull your interval data, work out your typical daytime load, and size to cover that first.

  Leave some headroom if you are likely to add a battery, an EV or a heat pump, but avoid paying for capacity whose only destination is a low feed-in tariff.

• Should I wait for solar prices or rebates to change?

  Waiting usually costs you. The panel rebate steps down every year until the scheme ends in 2030, and the battery discount steps down every six months, with the next reduction on 1 January 2027.

  Prices have been broadly stable, so delaying tends to mean a smaller rebate rather than a cheaper system. That said, a step-down announced months ahead is not a reason to sign the first quote you are handed.

Written by

Mariam Gabaji

Senior Utilities Editor & Tech Expert

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Mariam Gabaji is a journalist with 13 years of experience, specialising in consumer topics like mobile services and energy costs. Her work appears in the ABC, Yahoo Finance, 9News, The Guardian, SBS, 7News, A Current Affair and Money Magazine. Mariam holds a Bachelor of Arts in Journalism and was a finalist for the 2024 and 2025 IT Journalism Award for Best Telecommunications Journalist. See full bio

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