Guide to Buying Solar > 7. Best Solar Inverters
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The title for best grid-tie solar inverter has never been closer as many of the top manufacturers release advanced new models with clever online monitoring and smart home energy management features. The hype around home battery systems or hybrid systems is also growing, but it is early days for batteries and the majority of solar installations still require a dedicated solar inverter. Even the renowned Tesla Powerwall with its inbuilt inverter requires an additional solar inverter to work with a solar array.
Solar Inverter function & problems
The solar inverter is the most sophisticated part of any grid-tie solar system and unfortunately it's also the part most likely to have issues. This is not surprising considering inverters are usually located outside in harsh weather conditions including rain, humidity and extreme heat, all while generating thousands of watts of power for up to 10 hours a day. This is why it's important to use a quality inverter and mount it in a sheltered location if possible.
Due to extreme variations in humidity and temperature, it is likely that many inverters mounted outdoors will experience a fault at some point during their lifetime. However, the life of a solar inverter can be significantly increased by locating it inside a garage, under a carport and out of direct sunlight.
Solar panels can also develop problems over time which can result in poor performance, but unlike a faulty inverter this will generally not result in complete system shutdown. With this in mind, it is worth while paying the additional cost for a reputable manufacturer (one which has been in good business standing for 5+ years and with extended warranties if available.
Warranty and Service
Fronius and SMA have ranked on top of the list for many years due to the low failure rates and great service, as they usually ship replacement units in 3-5 business days. Fronius, SMA, ABB, Sungrow and Huawei are all available with 10-year warranties, while SolarEdge offers a 12-year manufacturers warranty as standard. Many of the 'value' brands now also offer 10-year warranties but some will only repair a faulty unit if it is shipped to them (at the owner costs) and returned, which can takes weeks and sometimes months. This will have a much greater financial impact due to system downtime.
Solar Inverter Types
String Solar Inverters
This review is focused on common 'string' solar inverters which are the most popular type of solar inverter. These inverters are connected to a string of solar panels linked together in series. String inverters are the most common type of inverter used in Europe, Australia, & Asia, and are growing in popularity in the US where micro inverters are also very popular.
Hybrid or battery ready inverters combine a solar inverter and battery inverter together in one simple unit. Most can also provide a basic level of backup power in the event of the blackout. These inverters are becoming more competitive against solar inverters as hybrid inverter technology advances and batteries become cheaper and more appealing. For more details, see our detailed hybrid/off-grid inverter review.
Off-grid or stand-alone power systems require powerful battery inverters with inbuilt chargers which can be setup as either AC or DC coupled solar systems. Modern, flexible off-grid inverter/chargers, also known as multi-mode inverters, can also be used to create advanced hybrid grid-connected systems. See the best off-grid solar systems review for more information.
Small scale and DIY off-grid systems use simple solar charge controllers, also known as MPPT solar regulators. These are not inverters, but solar battery chargers connected between the solar panel/s and battery to regulate the battery charging process and ensure the battery is charged correctly, or more importantly, not over-charged.
Micro inverters, also known as micros are very small solar inverters attached directly to individual solar panels. Since each micro inverter and panel operate independently, they are a great option for complex roof layouts and locations with shading issues. Despite the slightly higher cost, micros are very popular in North America due to Enphase’s strong presence and the many advantages they offer over string inverters.
Inverter Rating Criteria
The following criteria was used to determine the best solar string inverters available on the market, together with continuous feedback from solar installers and our industry specialists in Australia and North America. Note, this comparison is focused on common grid-tie solar 'string' inverters (single phase).
Quality & Reliability
Service & Support
There is a considerable price difference between the hundreds of different solar inverters available. For example, an entry-level 5kW inverter can start from as little as $750, while a premium quality 5kW inverter with 10+ year warranty may cost $1700 or higher. However, considering the high failure rates of many low-cost inverters and difficulty claiming warranties, we recommended investing in a higher quality unit. As a common saying in the solar industry goes “the cheapest products will cost you more in the long run”.
Best Solar Inverters 2021
* Extended warranty options available - may vary depending on country
Detailed comparison chart of the leading solar inverters
Best Commercial Solar Inverters
While this article is primarily focused on the leading residential, single-phase string solar inverters, most manufacturers also produce a range of inverters designed for larger 3-phase residential and commercial applications. String solar inverters up to and above 100kW are also increasingly popular for use in utility-scale solar farms due to the advantages of string level monitoring and ease of servicing compared to single central inverters. Below is our list of the most popular 3-phase inverters on the Australian market in the 8kW to 30kW, and 30kW to 100kW categories.
Best 3-phase solar inverters - 8kW to 30kW
Fronius - Symo and Eco
SMA - Sunny Tripower range
SolarEdge - SE 3-phase
Sungrow - SG & CX range
Huawei - SUN2000-KTL range
Best 3-phase solar Inverters - 30kW to 100kW+
SMA - Sunny Tripower Core 1
FIMER (ABB) - PVS-TL
Sungrow - CX range
Huawei - SUN2000-KTL range
SolarEdge - SE range
Have your say - Solar professionals feedback
In addition to continuous feedback from our solar specialists, the clean energy reviews team invite all solar industry professionals and installers to provide feedback (positive or negative) from experience with any inverters (string, micro, off-grid & hybrid). Click the link below.
Solar system monitoring
All solar inverters come with some form of remote monitoring which and is an important tool needed to track system performance. Without reliable and accurate monitoring, it’s difficult to know if a solar system is operating correctly or requires some form of maintenance.
In this review, we place a strong emphasis on system monitoring as well as electricity consumption monitoring which is an essential part of a modern solar system. Most inverters can track both solar generation and consumption with an additional energy meter. Learn more about the importance of consumption and system monitoring.
top 5 Solar inverters - Residential
Below we describe the top 5 residential solar ‘string’ inverters for 2019 based on quality, features, monitoring, warranty and service, together with feedback solar installers and industry professionals. In addition, there are a number of popular inverter brands which are highly regarded by many solar installers listed in the runner up section below.
Fronius Inverters have maintained the top spot for much of the last eight years, ever since the release of the innovative snap-in design in 2012. These Austrian manufactured inverters have become the inverter of choice for many domestic and commercial solar installations due to the proven performance and reliability, plus the great service from the Fronius support team. However, high demand for the popular single-phase Fronius Primo inverters used for residential installations has resulted in some supply issues, and there have been some minor faults. Still, overall feedback is very positive, and any issues have been promptly corrected. An additional free five years extended warranty is available when the inverter is registered online, which gives a total ten warranty period.
See the detailed Fronius Solar Inverter Review.
Active cooling system
One of the reasons for Fronius’s reliability and performance is due to the ‘active cooling’ system incorporated into all Fronius snap-in inverters. Active cooling is also a key design feature in the new generation Fronius GEN24 hybrid inverters due for release early in 2021. The fan forced cooling system extracts heats at a higher rate which reduces thermal stress and can increase power output in high ambient temperatures. All power electronics have a maximum operating temperature after which the power needs to be reduced to prevent overheating and potential damage. This is where active cooling can help improve both reliability and performance. Other features include the integrated DC isolator and the unique snap-in design makes servicing and installation very simple.
The larger capacity Fronius 3-phase Symo and ECO inverters are regarded as some of the best small commercial inverters (up to 30kW) and have dominated the market due to their high quality and proven reliability.
Wifi monitoring comes standard with all inverters via the Fronius Solarweb. The addition of the Fronius Smart meter enables monitoring of energy generation and consumption and can be used as a complete home energy monitoring system. The Fronius Solarweb app is an easy to use app which displays solar generation, consumption and estimated savings. The analysis section offers detailed operating statistics like string current and grid voltage. However, only 3 days of consumption monitoring data can be accessed without a premium subscription to the Fronius Solarweb. The premium upgrade offers some great features but considering most competing platforms offer free usage and generation history, this is a little disappointing.
See the detailed Fronius Primo Inverter specification sheet
SolarEdge inverters have becoming increasingly popular in Australia, USA and around the world over the last few years due to the unique design using DC optimisers which enables individual solar panel level power optimisation and control.
The the compact SolarEdge HD wave (SE-H series) inverters are available in a wide range of sizes from 2.5kW to 10kW. All Solaredge inverters must be installed with an additional DC optimiser fitted to each panel. The optimisers perform part of the job of a typical string inverter but have several benefits including panel level monitoring and power optimisation - See the detailed SolarEdge Review for more information.
Solaredge DC Optimisers are small electronic modules attached to the rear side of each solar panel which enable each panel to operate at it’s maximum power level. Panel level optimisation can also be obtained through the use of micro-inverters, plus some add-on power optimisers such those from Tigo Energy.
Solaredge Optimisers also enable longer strings of panels (up to 22 modules), offer rapid shutdown for increased safety, help reduce the detrimental effects of shading, and can provide early detection of potential issues. However, optimisers also add more complexity to the system and any electronic device mounted on the roof also has the potential to cause issues in the longer term. SolarEdge also has an extended 12 year warranty period.
SolarEdge inverters have 'optional' wifi which together with the optimisers can provide power output data for each panel individually. This is great for both system monitoring and a very good tool for fault detection, especially for installers. Also SolarEdge definitely have one of the best smart phone apps for remote system monitoring. See the full SolarEdge monitoring system and features here.
See detailed SolarEdge Solar Inverter specification data sheet
German manufacturer SMA Solar Technologies was widely regarded as the best string inverter manufacture before the Fronius snap-in series took the top spot in 2016. However, the new Sunny boy AV series regained a lot of market share after SMA relocated all manufacturing back to Germany in 2019. SMA inverters have a proven track record for reliability and are generally considered one of the highest quality inverters available. Local service and support is excellent and SMA provide an optional 10 to 20 year extended warranty.
The 3-phase inverters from SMA are all manufactured in Germany, and the new Sunny Tripower series are regarded as some the best commercial inverters on the market. SMA has also cemented its place as one of the industry leaders in the utility-scale solar inverter market with the impressive Tripower Core 1, Sunny Highpower and Sunny island central inverters.
Like many other new inverters, the latest AV inverter series from SMA does not have a display and relies solely on Wifi communication for setup and monitoring. Display-less inverters have become more common as a digital display in an outdoor environment can fail over time. The display-less design may reduce faults and warranty issues in the long term, but only if wifi communication is very reliable and stable.
See the detailed SMA solar Inverter review article.
SMA have a free online monitoring package called the Sunny portal and most SMA inverters now come with Wifi webconnect capability as standard. Full consumption and solar monitoring is achieved using the rather expensive additional Sunny home manager 2.0 energy meter. The only major downfall is the SMA mobile app which looks very dated and has received poor feedback, particularly the Android App version. However, the new SMA 360° App should make life much easier for installers when commissioning new systems.
See full SMA solar inverter specification data sheet
Founded back in 1997 by a university professor, Sungrow is one of the largest suppliers of solar inverters globally and a leading Chinese inverter manufacturer. The residential SG range of inverters have become very popular among installers due to the competitive price and great reliability record. Sungrow is a very large player internationally and has a good reputation for service and quality. The very good support from the Sydney based office in Australia has further helped improve their reputation.
See the detailed Sungrow solar Inverters review article.
In addition to the well regarded range of solar inverters, Sungrow also manufacture one of the best value hybrid solar inverters on the market - the third generation SHK5-30 is a very affordable hybrid inverter for home energy storage systems and now comes with integrated back-up for powering basic essential loads during a blackout.
The premium SG series solar inverters and SH5K-30 hybrid inverters have received very good feedback, are great value for money, and are now backed by an extended 10 year warranty.
Sungrow inverters include Wifi monitoring as standard on all models and use the new modern cloud based monitoring portal iSolarCloud which is a huge improvement. The free smart phone App is also very simple and works well. One small issue is the consumption monitoring has been noted to be problematic.
Chinese communications giant Huawei stormed into the residential solar market in 2018 with a compact, lightweight solar inverter packed with features. Due to the huge volume of commercial & utility-scale inverters sold globally, Huawei is one of the worlds largest solar inverter manufacturers and have invested billions into research and development over the last decade.
The first generation residential inverter from Huawei was the SUN2000L, available in a range of sizes from 2kW to 5kW while the updated version was released in 2020. Like the first version, the new SUN2000L1 inverter also functions as a hybrid inverter but works with the more powerful SUN2000-450W-P optimizers and the new Huawei LUNA2000 battery system. The inverter is in some ways similar to the SolarEdge HD wave inverter which use optimisers for individual panel optimisation much like micro inverters. However, unlike the HD wave, the Huawei inverters can function with or without optimisers. As a hybrid system, the Huawei inverter uses a built-in 'high voltage' DC coupling battery interface which is compatible with the popular LG chem RESUH battery and the new LUNA2000 battery.
The new optional backup-box works with either the LG Chem HV or the new Huawei battery and features a 5kW backup power rating which is more than enough for essential loads. For more information see the complete Huawei inverter review article.
The new FusionSolar app and online monitoring portal is much better than the previous FusionHome app and offers an easy to read interface and many more advanced monitoring and data logging features. The updated FusionSolar app is also used for inverter setup and direct connection via a local wifi network.
See full specifications of the new Huawei SUN2000-L1 inverter
Background - In a surprising move, ABB decided to sell its entire solar inverter division to FIMER, a well established Italian based inverter manufacturer who took over ABB’s solar division in early 2020.
Prior to the buyout, ABB was a premium manufacturer offering a range of high-quality string solar inverters but gained a poor reputation from the old 'Aurora' branded inverters. ABB acquired Aurora 'Power-one' back in 2013 and thus had to deal with old warranty claims and service issues from the old generation Aurora inverters.
With the FIMER takeover and positive feedback on the new range of UNO-TL and UNO-TL-DM-PLUS inverters, it’s likely FIMER will maintain and built a strong market position going forward. Feedback so far has shown the new owner has improved on the previously slow customer support and service offered by ABB.
The UNO range of inverters have the common plug & play interfaces and wifi included on all models. To compete in the growing energy storage market, the second generation REACT 2 hybrid inverters from FIMER are a unique modular battery energy storage system (BESS) which can be either AC or DC coupled.
System monitoring is probably the biggest weak point on the DUO range, although the updated Plant Viewer monitoring portal and ‘Energy Viewer’ mobile App is an improvement. The portal offers basic information but unfortunately it is quite limited and doesn’t provide much technical data such as individual string outputs or voltages, which helps with monitoring and troubleshooting. A Wifi logger card (VSN300) can also be installed on all older UNO and TRIO (3-phase) inverters to enable monitoring.
Solar Inverters - Runners up
Besides the most popular inverters currently on the market, many other well-known manufacturers are producing high-quality solar inverters for the residential and commercial solar markets. Many of these brands are trusted and very reliable; however, a few are let down by poor service and support when an issue occurs or if a warranty claim is required.
Delta is generally regarded by solar installers as one of the best quality entry-level inverters. This is not surprising as Delta Group is a global electronics giant which has been manufacturing power control systems around the world since 1971. Despite the older RPI range not being a huge hit with installers, the advanced new Delta Home Series inverters are becoming much more popular.
The new H5A-222 inverter is a standout product with a built-in (certified) DC isolator, inbuilt energy meter, and incredibly low PV startup voltage of 35V. This means the inverter has a very wide operating voltage window and will start generating very early in the morning before most other inverters have even woken up. Plus the inverter can operate with only 1 panel (per MPPT); however, in practice, 2 panels would be required taking into account temperature variances. In contrast, most of the competition require 3 or more panels to start generating power. Delta has a 5-year product warranty as standard and an Australian office located in Melbourne.
Monitoring is via the cloud-based mydeltasolar app. The app was reported as being a little unreliable, but it now appears Delta has made some significant improvements to both the user experience and the commissioning process for installers setting up inverters.
GoodWe is a large, well known Chinese inverter manufacturer established in 2010 and the new generation Goodwe DNS series inverters have had great feedback from installers so far. In a surprise annoucment, Global electronics Giant, GE has partnered with Goodwe to produce a new premium range of high-performance solar inverters. Due to the extremely high demand for rooftop solar, GE will launch it’s new Goodwe made inverters into the Australian market during Q4 2020.
In regards to energy storage, Goodwe now offer a wide range of hybrid inverters. The GW5048D-ES hybrid inverter is a standout product from Goodwe and well regarded in the industry with many manufacturers incorporating this powerful hybrid inverter into various battery energy storage systems (ESS). All Goodwe inverters include Wifi monitoring as standard. The Warranty on the DNS series is 5 years with options to extend the warranty up to 25 years. The new Goodwe SEMS system monitoring portal is a great, detailed platform for monitoring both PV and energy storage systems.
See the full Goodwe DNS solar inverter specifications data sheet
Solax Power is a relatively new inverter manufacturer which was largely unkown in the industry until they launched the economical battery X-hybrid inverter. Solax is a subsiduary of the the much larger Suntellite Group in China which manufactures solar cells, panels and inverters with a strong emphasis on research and development. Solax Power also has a strong global presence and an Australian support office located in Melbourne. The current X1 range of solar inverters may not have the sleek designs of the European rivals but at close to half the price you wouldn't expect them to compete on this level, their slogan sums them up nicely 'simple, reliable, efficient'.
One of the more advanced inverter options from SolaX is the affordable X-hybrid unit which is one of the most economical ‘battery ready’ solar inverters available. Solax is also one of the few inverter manufacturers to produce large 3-phase hybrid battery inverters for larger residential and commercial applications.
The Solax online monitoring portal V2 is quite impressive and offers access via smart phone apps or web interface with battery management features for hybrid systems and email reporting, although the wifi dongle is an optional extra.
See the full Solax Inverter specification here
Growatt entered the solar inverter market back in 2010 and has grown rapidly to become one of the worlds largest inverters manufacturers. Based in Shenzhen China, Growatt’s first-generation entry-level solar inverters gained a poor reputation for quality and reliability. But to their credit, the company pushed through and backed its product by servicing many of the warranty claims. Growatt has since released a vast array of inverters which have had very good feedback so far. Growatt now offers a range of solar and energy storage inverter solutions for residential and commercial applications. Still focused on the entry-level market segment, many of the new models have been available for less than 2 years and are yet to prove themselves in the long term. Growatt seems very keen to improve their position and have established local support centres in many countries offering good service in the event of a failure or warranty claim.
The new generation TL-X inverter range is modern looking and available in a range of sizes from 2.5kW to 6.0kW, with dual MPP trackers and a standard 5 year warranty, 10 year warranty options are also available. The monitoring platform, known as ShineServer and ShinePhone (app), is also greatly improved and now offers a good user interface, remote parameter settings, and remote firmware upgrades.
Ingeteam is a large, premium European inverter manufacturer which is trying to enter the very competitive Australian solar market. The large multinational company of Spanish origin has a long history in manufacturing power conversion equipment, advanced R&D capabilities and currently produce a wide range of quality solar and hybrid inverters for the residential and commercial markets, plus powerful utility MW scale central solar inverters.
The residential (2.5 - 6kW) 1Play TL-M series dual MPPT solar inverters appear well engineered with many advanced features and monitoring. However, as yet our Australian specialists have had limited direct experience. The Ingeteam IS Storage 1Play hybrid inverter is a stand out product in that it’s the only hybrid inverter which can operate with both low voltage (48V) and high voltage (up to 300V) battery systems. Looking forward to seeing more Ingeteam inverters in the future.
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