Are you thinking about installing a home solar power system? How do you know which solar panels are the best?
Here’s a quick guide to the essentials of solar panel comparison.
- Tier-1, Tier-2, or Tier-3 solar panels: What’s the difference?
- Solar Panel Warranties: What should you look for?
- Power Tolerance: What is it?
- Solar Panel Efficiency: What’s good or bad?
- SolarPpanel Performance Ratio: What is it?
- Temperature Coefficient: What is it?
Deciding to install a solar energy system is a big deal! Solar technology is a long term investment. Choose well and you’ll enjoy cheap or free electricity for many years without problems. Get it wrong and you’ll be dealing with some serious headaches in the coming years.
TIP: Take your time deciding and make sure you’re clear about everything before proceeding. Time spent learning and researching about what you need and which system will meet those needs is time well spent.
The solar marketplace in Australia is growing. And the choice of solar panels is impressive. Some might say overwhelming! There are an estimated 10,000 solar panel models approved by the CEC for installation in Australia.
More choice is better, right?
Not always. You can get bogged down in technical aspects which aren’t that important. And every solar panel installation company will tell you their panels are the best. But there are a few key things you should look at when comparing solar panels.
How Do You Make a Fair Comparison of the Solar Panel Models on the Market Today?
Here are 6 aspects of solar panels you can easily compare. You can get the information you need from the technical specification/data sheet for each panel you want to compare.
You don’t have to rely on salespeople for this information.
Comparing these 6 key factors will help you make the best buying decision regarding solar panels for your system.
1. Tier-1, Tier-2, or Tier-3 Solar Panels: What’s the difference?
Do you want top quality, medium quality, or budget solar panels?
Solar panels are ranked by tier, with Tier-1 panels being the best. The top reputable brands offer these and they provide excellent performance. Tier-2 and Tier-3 solar panels are of inferior quality. Although there are some good ones and some quite decent ones. But the risk of ending up with something which doesn’t last or causes problems is high.
The problem is that you need to be a technical expert to distinguish between the good, the bad, and the downright ugly!
Another reason to say away from Tier-2 and Tier-3 panels is that the companies manufacturing them are less established. There’s no guarantee they’ll still be around in 10 years if you have problems and need technical support.
Or if you need to make a claim on the warranty.
Many people think that solar panels are ranked on their efficiency and performance. And that’s how they are assigned a Tier 1, 2, or 3 classification. Not exactly true. The ranking system is really based on the manufacturer.
Large scale commercial solar farms use solar panels from big brand manufacturers. Because the investors (banks and other financial institutions) can be sure that the company is stable and will be around in the future.
So a Tier-1 solar panel actually represents the lowest risk to those buying them rather than simply the highest quality or best performance statistics.
Obviously, in the real world, there is a direct correlation between top brands and quality panels, service, performance and efficiency, etc.
Examples of Tier-1 solar panel manufacturers:
- Canadian Solar
- JA Solar
TIP: Unless you’re an expert, don’t even consider choosing Tier-2 or Tier-3 solar panels. Stick with reputable Tier-1 manufacturers for peace of mind – even if you’re not building a commercial solar farm! It’s a long-term investment, so go for the best you can afford.
2. Solar Panel Warranties: What should you look for?
First, be aware that there are two types of warranties associated with solar panels:
- Performance warranty
- Manufacturer’s warranty
The first one, the performance guarantee or warranty, you can ignore. All panels on the Australian market come with a performance warranty of 25+ years. It doesn’t really count for anything, because manufacturers can easily weasel out of this type of warranty with various technical excuses.
The important warranty to compare is the second one: the product or the manufacturer’s warranty. It’s typically a 10-year panel warranty although some of the big brand solar panel companies are now offering longer warranties. Look for a minimum of 10 years cover.
3. Power Tolerance: What is it? Why is it important?
The power tolerance of a solar panel is expressed as a ±% value. It measures the amount of electrical power a solar panel produces at any time in relation to its rated capacity. A 300-watt solar panel with a power tolerance of ±5% will produce between 285 and 315 watts under real conditions.
TIP: Don’t buy any solar panel with a negative power tolerance. Nowadays, all Tier-1 panels come with a positive power tolerance. So a 300-watt solar panel should be capable of always producing 300 watts (or slightly more). The proof you need is the ‘flash test’ certificate. This shows the verified power tolerance of a panel.
4. Solar Panel Efficiency
The efficiency of a solar panel measures the solar energy (sunlight) the solar panel converts into electricity you can use. High-efficiency solar panels can have a rating of up to 23% but regular solar panels have an average efficiency between 15% and 18%.
Choose solar panels with a minimum of 15% efficiency. The real advantage of high-efficiency solar panels is they produce the same output as regular panels but occupy less space on your roof.
So unless you have really limited roof space, don’t worry about spending extra just to get high-efficiency panels. Regular ones will do fine.
5. Solar Panel Performance Ratio: What is it?
The performance ratio (PR) metric is a useful quality measure. It’s expressed in percentage form and is independent of geographic location. It shows the real-world power output of the panel in relation to its theoretical power rating output.
So a 300W solar panel with a PR of 90% will only produce 270W in the real world.
Top brand Tier-1 solar panels typically have a PR of around 90. You can expect a PR of 92% from the best panels. Don’t settle for any solar panel with a PR lower than 90%.
6. Temperature Coefficient: What is it? Why is it important when comparing solar panels?
Solar panels are designed to ‘collect’ sunlight. But excessive heat negatively affects their performance. As a solar panel becomes hotter, its power output drops.
The temperature coefficient is a metric which shows the decrease in panel power output per degree rise in temperature of the panel.
Typical temperature coefficients are between -0.4%/°C and -0.5%/°C. The lower the value, the better. There will be less loss of power output.
Some of the best solar panels on the Australian market have even lower temperature coefficients, like the LG solar NEON2 model (-0.37/°C).
Why is This Metric Important?
Example: The working temperature of a solar panel with a temperature coefficient of -0.5/°C rises by 20°C. This means that the power output of the panel will drop by 20 × (0.5) = 10%.
With a temperature coefficient of -0.37°C, the drop in solar panel power output will be only 7.4%.
Ideally, you want the least drop off in power output because it will affect overall solar energy system efficiency. You’ll have less electricity production for home use and make fewer savings.
Solar Panel Comparison Key Points
TIP: Don’t get too bogged down in technical specifications. Keep it simple and focus on these key points:
- Efficiency rating: a less efficient panel is bigger but cheaper. A higher efficiency panel is more expensive but smaller. They both generate the same power.
- Temperature coefficient: the hotter a panel array becomes the less efficient it is. Go for the best temperature coefficient you can afford for optimal power output.
- Warranty: Focus on the manufacturer’s or product warranty NOT the performance warranty. It’s better to prioritise prompt and excellent after-sales support, warranty service, etc. than chase a few % points extra of module efficiency when choosing.
TIP: Avoid lengthy discussions about solar cell technology, and different cell types. Many people obsess over whether monocrystalline solar cells and monocrystalline panels are better than polycrystalline solar cells and polycrystalline panels.
For a regular residential solar system in Australia – they’re both perfectly fine!