How to Choose the RIGHT Solar Panels for Your Home

Sizing Your Solar System for Year-Round Savings

Want to know the biggest mistake you can make when buying solar panels? It's not choosing the wrong brand, although avoiding the crap brands is important. It's not putting enough solar panels on your roof. Let me show you exactly how to choose the right type and number of solar panels for your roof without any of the solar sales bullshit.

First, let me tell you how much solar you're gonna need to keep your bills down all year round. Spoiler alert, it's probably more than you think. Here's the rough maths.

Now, a beginner's note here, one kilowatt-hour is one unit of electricity, which is about 40 cents worth. When you look at your bill, you'll see that you were charged in kilowatt-hours of electricity.

The typical Australian home uses 16 to 20 kilowatt-hours of electricity every day. Each solar panel makes on average about two kilowatt-hours of electricity every day. So you'd think 10 solar panels producing 20 kilowatt-hours on an average day would be enough for the typical Aussie home, right? Wrong. That would be way too smaller solar system.

That's because using averages is only for dim door-to-door salespeople. Those 10 solar panels might give you enough electricity to power through the middle of a long sunny summer's day, but what about winter? What about overcast days? What about mornings and evenings? That's where big solar comes in.

You must size your solar to get you through winter, not an average day. Here's my advice. Completely fill your north, west, and east facing roof with panels. Seriously, people worry about having too much solar, but that's a good problem to have.

"But what about making too much power?" I hear you ask. Look, if that becomes a drama, you can do one of the following. Find an electricity plan with the best feeding tariff, add a battery, move your water heater to switch on in the middle of the day, make sure your next car's an electric one, or if none of that is on your radar, no problem. Your installer can simply program your solar system to reduce the amount it generates when you don't need it and when the grid can't take it. Your solar panels will only produce what your inverter asks for, and your inverter can easily reduce your solar power right down to zero. It's just not an issue.

In solar jargon, we call turning down your inverter 'curtailment'. Some people think it's a waste of energy, but what are we wasting exactly, sunshine? Curtailing your solar is like when your rainwater tanks are full in the middle of winter and any more rain goes down the storm water drain. Not many would consider that wasting rain and go running out with buckets to catch every last drop. So don't worry about not using every last ray of sunshine that falls on your roof, but do make sure you catch the rays you really need in winter, in the morning, and in the late afternoons, and you do that with a big-ass solar system.

The bottom line, when it comes to solar panels, bigger is almost always better. Big solar gives you more solar in the morning and early evening when you need it most. More on days with crap weather and loads of spare for when you get a battery, electric car, or electric hot water heater.

Understanding Solar System Terminology

If you are getting solar, don't go smaller than about 20 solar panels. In solar speak, that's about a 10 kilowatt solar system. Most people in Australia will fit 20 to 40 panels on their roof.

Now, I need to explain some solar system jargon. In 2025, most residential panels are about 440 watts in size, but I'm gonna call it 500 watts to keep the maths easy.

Watts is a measure of power. A 500 watt panel will slowly ramp up its power through the day, starting at zero, ramping up to 500 watts at midday, and then dropping to zero as the sun sets.

Now, if you have two 500 watts solar panels, you've got 1,000 watts. That's commonly called a kilowatt. On a sunny day, those two panels produce a kilowatts of power around midday. If they produce one kilowatts for a whole hour, they've produced a kilowatt-hour of electricity. That hour is important. It turns instantaneous power in kilowatts into a kilowatt-hour, and that's a unit of electrical energy that's been generated over time.

Kilowatts is instantaneous power. Kilowatt-hours is energy generated or consumed over time. How solar panels turn power into energy.

If you can only fit 10 500 watt solar panels on your roof, you have a 5,000 watts or five kilowatt solar system. That will produce five kilowatts at midday on a sunny day. To convert that power rating into the average amount of energy produced by those solar panels every day, you need to multiply it by the magic number, four. So if you are quoted a five kilowatt system, expect 20 kilowatt-hours per day to be generated on average. A 10 kilowatt solar system will generate 40 kilowatt-hours per day on average, a 20 kilowatt solar system, 80 kilowatt-hours per day.

And remember, that's an average. Depending on where you are in Australia, you may get a quarter of that in the depths of winter and lots more over summer. Ask your installer to size your system for winter use. Obviously that calculation will be different for Tasmanians compared to folks living in Cairns. So use a local installer, not someone from a call centre in Southeast Asia who uses retired cricketers to support cheap solar on the telly.

- Good day, Australia. Rusty Balls here. If you're still getting a power bill, you're a bloody loser, just like the Zimbabweans back in '96. - It's Rusty Balls. - Come on, Australia, get dodgy, get solar, get dodgy solar.

Choosing the Best Solar Panels

Now, which solar panels are best? Let me cut through the sales spin and show you how to compare solar panels. No BS, no fancy marketing talk, just the stuff that really matters for your situation.

Differences in performance between solar panels have become really marginal these days. The vast majority are made in China, but chill out before you do a Pauline Hanson on me. The Chinese have gotten really damn good at making panels. Their factories are the most modern and highly precise in the world. If you want to compare the individual specs of major brands to see their differences for yourself, I've got a solar panel comparison table which I've linked to in the description.

The specs to check if you're a complete energy nerd are efficiency, temperature coefficient, and degradation.

Efficiency

Let's talk about efficiency. The higher the efficiency, the more energy you'll get from the same area of solar panel. Most good solar panels on sale in 2025 are 21 to 23% efficient. If you want to squeeze the most energy from your roof, go for a higher efficiency. The good news is that in 2025, budget panels are as efficient as the expensive ones so you don't have to pay more for higher efficiency. For example, the dependable budget Jinko brand makes panels over 22.5% efficient, which is up there with a super expensive REC brand.

Temperature Coefficient

Temperature coefficient. The lower the temperature coefficient, the less energy you'll lose on a hot day. "Say what?" Bear with me. Solar panels love sunlight, but they don't like the sun's heat. If the panel gets over 25 degrees C, they'll start to lose efficiency. If it's important to you to get the most energy on hot days, you might get 5% more energy on hot days from the panel with the lowest temperature coefficient compared to the panel with the worst temperature coefficient. Budget Aiko solar panels and top-end REC panels have excellent temperature performance, if that's important to you, probably not one to worry about if you live in Hobart.

Degradation

Finally, degradation. All solar panels get less efficient over time. The higher the degradation, the bigger the performance drop every year. A budget panel might degrade half a percent a year, losing 10% of its efficiency over 20 years, for example, from 22% efficient to 19.8% efficient. Whereas a top-end panel might only degrade at half that rate, going from 22% to 20.9% over 20 years. So your budget panel is in absolute terms only 1% less efficient than the expensive one, which means in relative terms, you're getting about 5% less energy from the budget panel overall. So not as bad as 'double the degradation' sounds. The takeaway here is, if you want the lowest degradation, buy the more expensive brands, like REC. But if you want panels that are thousands of dollars cheaper like Trina or Jinko, you won't lose more than about 5% energy yield from the bigger degradation.

Look, I'm an energy snob, so I put expensive RECs on my roof and I love them. I like knowing I'm getting top performance that will excel in the heat and degrade more slowly. But I'm about to cover my new man shed's roof with solar panels, and I'll be putting good budget Trinas on there because I want to save some money to buy some toys to go inside the shed.

Reputable Brands and Key Considerations

To help you choose, I put the solar panel brands that I trust on this chart. Cheaper panels to the left, more expensive to the right. If you want the up-to-date version of this chart, there's a link in the description. Any of these panel brands are a safe choice in my opinion. Just be sure to get them well-installed by a local. Will be there for you in the unlikely event that you need to claim on warranty.

To appear on my chart, brands must have an Australian office for warranty support. If a company doesn't have a presence down under, it's very easy for them to fob you off if you have any problems.

Their Australian office must be easy to contact by a phone or email. Having an office won't do you much good if you can't get in touch with them.

They must have a good reputation amongst installers I trust. This can be a bit contentious, especially when it's Friday night on Facebook and installers have tucked away a few VBs, but we look for a general positive consensus.

The panel must not have been flagged by the Clean Energy Council for any major violations. This is pretty straightforward. If the accrediting body for solar in Australia doesn't like a brand, we won't either.

Now let's talk about panel aesthetics. While the nerds might care about the panel performance, other householders might care more about the looks. "Hello, darling." The most common solar panels have a silver frame with a white back sheet. Then you have black frames with white back sheets. And finally, all black panels, black frames, black back sheets. I've got all black REC panels on my roof and they look mint to anyone passing in a helicopter.

On the topic of warranties, these days, the minimum warranty you should accept is 25 years warranty with some even going as high as 40 years, simple as that.

So finishing up, choosing solar panels doesn't have to be complicated. Stick with reputable brands, get as many panels as will fit your roof and budget, and most importantly, work with installers you can trust. Want to know exactly who I rate in your area? Head over to solarquotes.com.au right now, punch in your postcode, and I'll match you with up to three pre-vetted solar installers I trust who will compete for your business.

Solar Panel Technical Specifications

Frequently Asked Questions

Q: What is the biggest mistake people make when buying solar panels?

A: The biggest mistake is not putting enough solar panels on your roof. While avoiding poor brands is important, under-sizing your system means you won't generate enough electricity, especially during winter or on overcast days, to keep your bills down.

Q: How should I properly size my solar system?

A: You should size your solar system to get you through winter, not just an average day. The advice is to completely fill your north, west, and east-facing roof with panels. Don't worry about generating too much power, as excess can be managed through feed-in tariffs, batteries, smart appliance scheduling, or by programming your inverter to reduce generation (curtailment).

Q: What are the key technical specifications to consider when comparing solar panels?

A: The three most important technical specifications to consider are efficiency, temperature coefficient, and degradation.

• Efficiency indicates how much energy you'll get from a given roof area; higher is better.
• Temperature Coefficient measures how much efficiency panels lose on hot days; lower is better.
• Degradation describes how much less efficient panels become over time; lower is better.