An inverter is a piece of equipment in your solar system that converts direct current (DC) electricity into alternating current (AC) electricity. And what do you get when AC and DC run into each other? Well, you get a most excellent rock band – the pride of Sydney.
All jokes aside, you will need to decide between a microinverter solar system or a string inverter solar system when it comes to choosing the right equipment for your energy needs.
Inverters are so much more important to your savings than the solar panels. Inverters are the heart and soul of your solar setup. They are the bridge between your solar panels and your home’s electrical system.
Deciding on which type of solar system to invest in is a big decision that will inform all the other decisions you make about your solar investment. Which one should you pick?
At Penrith Solar, we install microinverters for most of our solar systems. We feel it’s important to give you an transparent comparison between microinverters and string inverters so that you make the decision that’s right for you. Sometimes a string system is perfect for your needs.
In this article, you will learn:
- What Are Solar Microinverters?
- What Are the Advantages of Solar Microinverters?
- What Are the Disadvantages of Solar Microinverters?
- What Are Solar String Inverters?
- What Are the Advantages of Solar String Inverters?
- What Are the Disadvantages of Solar String Inverters?
- Important Considerations to Remember
By the end, you’ll know exactly which inverter setup fits your needs and why it’s the best choice for powering your home. Let’s dive in!
What Are Solar Microinverters?
Why do your solar panels need an inverter (or microinverter)?
Here’s why: the electricity your panels create (DC) isn’t the same type your home runs on (AC). That’s where the inverter steps in — it’s like a translator for your solar system, making sure the energy your panels harvest can actually power your lights, appliances, and everything else.
Solar panels only produce DC (direct current) electricity, but your home can only use AC (alternating current) electricity.
Microinverters handle this translation at the panel level. Instead of one big inverter on the side of your house (called a string or central inverter), each panel gets its own micro-inverter to do the job.
This means your system is decentralised, so every panel operates independently. This gives you better efficiency and performance.
Microinverters take care of that right at the source, one panel at a time.
If you’re interested in learning a bit more about the inner workings of a microinverter solar systems, you might want to check out the following article titled, How Do Microinverter Systems Work?
What Are the Advantages of Solar Microinverters?
There are a lot of advantages to engineering a decentralised solar system featuring microinverters.
Independent Operation: Because each solar panel has its own microinverter, the power that each panel produces can be sent to the home directly. In a string inverter system, there is a central point of failure: the inverter itself. The string inverter on the side of the house converts the electricity from all the solar panels collectively.
That collective conversion from all the solar panels together has an unfortunate side effect: when one panel drops in efficiency, the string inverter thinks that’s the maximum output and drops the other panels to match it.
Because of this, in a string system, the panels work a little like Christmas lights. And much like a string of Christmas lights, when one goes out the others are affected. All the solar panels drop to match the weakest link.
This isn’t the case with microinverters. In a microinverter solar system, each panel works on its own with its own microinverter. There is no central point of failure.
This is the biggest advantage of microinverters. The efficiency of the overall system is divided, not centralised.
Here’s Another Example: Think of a solar system like the motorway.
- Microinverter System: A microinverter system has four lanes of traffic, and each lane has a car of its own. The flow of traffic is decentralised across four lanes.
- String/Central Inverter System: It has four cars right behind each other in one lane. If anything happens to the speed of the first car, the other three slow down to match it.
Which one sounds better to you? It’s an issue of efficiency.
Shading: Solar panels need direct sunlight to produce electricity. That’s just how they work. If a big, gorgeous tree shades your panels, they won’t be able to harvest energy for your home during that time. It’s a simple fact of science.
Microinverters excel in scenarios with shading because each panel operates independently. Shading on one panel does not affect the performance of the panel next to it. If some of the panels are receiving full sunlight, they will still produce at full power. They are extremely efficient systems because of this.
A string inverter system will suffer from shading. The panels do not operate independently. When one is shaded or partially shaded, the entire string reduces its performance.
The entire system can only perform as well as the poorest performing panel. It’s like a group project where everyone’s grade depends on the laziest team member. Not ideal, right?
Panel Orientation: No two roofs in Sydney are exactly alike. Sure, you’ll get the occasional cookie-cutter housing development, but for the most part, every solar system ends up with its own unique design. For the most part, every solar system will need to be customised a bit once your installer factors in roof real estate and your household’s energy use and needs.
This is where microinverters make life easier. They allow for a lot more flexibility in system design because each panel works independently.
Panels facing different directions perform more efficiently:
- Panels facing east generate power in the morning.
- West-facing panels generate power in the afternoon.
- Combining them offers a more even distribution of energy throughout the day.
For more information on energy consumption patterns and how they impact the design of your solar system, you might want to check out this article titled Which Way Should Solar Panels Face in Australia?
Enhanced Safety: The direct conversion of energy from DC to AC at each panel reduces safety risks associated with high-voltage DC systems. DC electricity behaves differently from AC electricity.
- DC power moves in a straight line of consistent power.
- AC power alternates 50 times a second in a sinusoidal waveform.
The science and engineering that explains how DC power is more dangerous in solar systems than AC power is complicated. It basically comes down to how easy it is to shut the system down.
- AC Systems (microinverters): Because a microinverter system converts the electricity from DC to AC at the panel level and then sends it down to the main switchboard, it can be completely shut down in the event of an emergency.
- DC Systems (strings inverters): A string inverter system, which has a central inverter on the side of the house, keeps that electricity in its more volatile state as it journeys through the wires to the main switchboard. This architecture prevents it from fully shutting down.
Regardless of the type of system you put up on your roof, having a good installer who knows their business is the biggest safety feature for your home. The risk is only an issue in the case of an emergency where the wire is compromised.
Reliability: Microinverters have a warranted lifespan of 25 years. It is twice as long as any of the best string inverter systems.
Real-time Monitoring: Microinverter systems come with a monitoring tool that let you track each panel’s performance. It’s an app on your smartphone called Enphase Enlighten. It’s also available on the web through your internet browser.
This information is extremely helpful when it comes to making choices around your energy needs and goals. If you know when you use power generated by the solar panels versus when you use power from the electrical grid, you’ll be able to make choices to save money and energy.
Microinverters, for instance, let you monitor each panel individually. This makes it simpler for technicians to pinpoint issues and address them quickly. Tools like the Enphase Enlighten App can help identify exactly where the problem is, so by the time we show up, we’re ready to get to work.
Our team comes prepared for every service call, ladders and all. The goal is always the same: make sure your system is efficient, reliable, and saving you money.
Expansion/Future Proofing: Thinking ahead about expanding your solar system has become an important factor for many people considering solar. This is sometimes called “future proofing.”
It’s smart to build a system that fits your energy needs at the time of installation. These decisions should be based on how your household uses energy now.
But energy needs can change. Maybe you’ll want to add a battery later, get an electric vehicle that needs a charger, or install extra panels as your power usage grows.
Microinverters make adding panels down the road easier. Since each panel works independently, you can simply add new panels and connect them to your existing system. It’s a plug-and-play process that keeps things simple.
With string inverters, you’ll need to add additional components. They’re very challenging to upgrade once installed. We’ll get into this in more detail shortly.
If you’d like to learn a bit more about how we service microinverters, you might want to check out the following article titled, Is It Hard to Replace Enphase Microinverters?
What Are the Disadvantages of Solar Microinverters?
Higher Upfront Cost: Microinverter systems generally come with a higher upfront price tag.
With some installers, these systems can cost 20 – 30% more than string inverter systems. However, the actual cost difference depends on the size of the system.
At Penrith Solar Centre, for example, microinverters are often competitively priced — and in many cases, they’re even less expensive than string systems as the system size grows. The larger the system, the more affordable microinverters can become. This due to economies of scale.
When comparing costs, it’s important to think beyond just the initial price. Solar systems pay for themselves over time through the money you save on your electricity bills.
A microinverter system might cost more to install in some situations, but its higher efficiency means it generates more power for your home, which translates to greater savings over the years.
In short:
- String inverter systems: Lower upfront cost, but higher long-term expenses due to potential inefficiencies and maintenance needs.
- Microinverter systems: Higher upfront cost, but lower long-term expenses due to better efficiency and durability.
Manufacturer Dependence: It’s also worth considering how fast solar technology is evolving. There’s no way to predict what innovations might come along in the future or how they’ll integrate with existing systems.
For example, a new technology could be developed that doubles panel efficiency—but it might only work with certain types of inverters. While this is purely hypothetical, it’s something to keep in mind when making your decision.
For more detailed information on the cost of microinverter solar systems, you might want to read the following article: How Much Does a Microinverter Solar System Cost?
What Are Solar String Inverters?
String inverters (also known as “central inverters”) are another type of inverter used in solar systems. Unlike microinverters, string inverters are centralised devices that convert the DC power from a group of panels (a “string”) into AC power.
Microinverters and string inverters both handle the job of converting electricity — but they do it in a different spot. String inverters are typically installed on the side of your house near the main switchboard. Instead of having one inverter for each panel (like with microinverters), you’ve got one central device doing the work for the entire system.
What Are the Advantages of Solar String Inverters?
Cost: String inverter solar systems are cheaper. The upfront cost is lower and there’s the potential, as mentioned above, for them to pay themselves off rapidly; quicker than a microinverter solar system.
A string inverter system that outputs 6kW of power will cost less per kilowatt than a microinverter system that outputs the same amount of power.
Installation: String inverters have been around since the early days of solar, so they’re a tried-and-true technology. Most solar companies and electricians know how to install them, making them widely available and easy to maintain. If you’re looking for something familiar and straightforward, string inverters are a solid option.
Compatibility: String inverters are pretty versatile when it comes to working with different solar panel brands and models, as long as the components match the inverter’s specs.
This flexibility means you can mix and match equipment to keep costs down, and if something needs replacing, it’s usually not hard to find compatible parts. Plus, most installers are experienced with these systems, so repairs or upgrades tend to be simpler.
If you’re interested in learning a bit more about shopping for a solar system, you might want to check out the following article titled, 6 Mistakes to Avoid When Buying Solar.
Embrace solar, embrace savings
What Are the Disadvantages of Solar String Inverters?
Central Point of Failure: As we mentioned, string inverter systems can have a bit of a downside when it comes to reliability. They work like a string of Christmas lights — if one panel stops working, it affects the entire system.
This can make diagnosing and fixing the issue more complicated and time-consuming. It’s not always easy to pinpoint exactly where the failure happened in the string, which can add to the cost of repairs.
On top of that, there’s the loss of solar energy while the system is offline. Depending on the issue, your home could be without solar for weeks, which means missing out on free electricity during that time.
Shading: One of the challenges with string inverters is how shading on a single panel can impact the entire system. Like we mentioned earlier with the motorway analogy, the slowest panel forces all the others to match its lower efficiency.
If one panel is partially or fully shaded, the whole string’s performance drops, even if the rest of the panels are in full sunlight. Another drawback is that string inverter systems don’t offer the same level of real-time monitoring as microinverter systems. Since the system measures the performance of the entire string, it’s hard to tell which specific panel is underperforming without a detailed inspection.
Here’s this graphic again so you don’t have to scroll up:
This makes it difficult to optimise your solar system and repair it when it’s underperforming.
Safety: String inverters don’t convert the DC power to AC power at the panel as microinverters do. A string inverter does this on the side of the house where it’s installed. The DC current travels across your roof down to the house, increasing the risk of an electrical fire because it’s in a high voltage state for that journey.
Of course, a good installer who understands the ins and outs of string inverter systems will know how to install this type of system as safely possible.
Noisy: Fans keep a string inverter solar system cool and make a fair amount of noise. In the summer, you won’t be able to ignore the drone of those fans.
If you’re interested in learning why other solar companies recommend a string system, you might want to check out the following article titled, Why Do Companies Sell 6.6kW String Systems with 5kW Inverters?
Important Considerations to Remember
Solar power is a great way to help the environment and cut down your energy bill. Often, it’s a significant investment so choosing the right equipment for your system is important.
Before deciding between microinverters and string inverters, consider the following:
Budget: Microinverters usually cost more upfront, and string inverters cost less upfront. Over time, the cost reverses as strings cost more in terms of efficiency over time and micros make more money long term. If you don’t mind some of the safety risks involved with string inverters, it could be the way to go.
Roof Design: Microinverters handle shading and different panel directions more efficiently. String inverters work well when the panel orientations are simple. If your installation is relatively simple, a string inverter system might be better for you.
Property Lifecycle: Microinverters offer flexibility for expansion and have a longer lifespan. String inverters are shorter-term investments for less money. Future modifications are an important consideration. String inverters are difficult to upgrade, and the cost will be significant if you want to do that. You might even need to replace the whole system. Microinverter systems can easily add additional panels to an existing array.
Compatibility: Microinverters rely on manufacturer support and advancements. String inverters are serviced by almost anyone. Which might make a difference in secluded or remote regions where servicing your solar system could be challenging.
If you’re interested in learning a bit more about the process of choosing components for your solar system, you might want to check out the following article titled, How to Shop for a Solar System.
Which Inverter is the Best?
We hope you feel a little more informed about microinverters and string inverters. It’s an important decision to make when choosing your solar system. The more you know about these pieces of technology, the better decisions you’ll make around your solar investment.
Choosing between microinverters and string inverters comes down to your specific needs and circumstances. By considering factors like cost, shading, and system size, you can make a decision that aligns with your goals.
Picking a trustworthy installer for your solar system is an important part of the decision process. Penrith Solar Centre is here to help you find the best fit for your home, and that starts with helping you get informed about this decision. We want you to be an informed shopper and we want you to make the best decision for your unique energy needs.
The goal is to reach Net Zero by 2050. For all of us.
If you’re interested in learning a bit more about how microinverters compare to string inverters from a cost point of view, you might want to check out the following article titled, Cost of Microinverters vs. Cost of String Systems.
