When purchasing solar panel systems for your home or business, an important question is asked: which type of inverter is better for my system – a micro-inverter or a central (string) inverter?
Both types of inverters convert the direct current (DC) produced by your panels into the usable alternating current (AC) that powers your electrical appliances. The difference between the types of inverters starts with how many are installed with your panel system and goes on to the short and long term costs associated with both. Let’s start with the physical differences.
Micro-inverters have been around since the 1990’s and are roughly the size of an internet router. Micro-inverters are installed at each panel, allowing for maximization of the individual panel’s energy production. A PV system containing 30 panels, for example, would have 30 micro-inverters installed. There are some micro-inverters that connect to two panels, but the system would still have 15 micro-inverters total, instead of one central inverter. One of the biggest benefits of micro-inverters is that one solar panel with lower performance can’t reduce the performance of the entire system. Micro-inverters are especially useful on properties where the solar panel array is installed on multiple angles, such as roof planes that face different directions. They are also beneficial for systems that have coverage issues- such as shading, dirt, or snow. Shading on as little as 9% of a panel array that is connected to a central inverter can lead to as high as a 54% decline in total system performance. This is a big decline that can be avoided by using micro-inverters.
Central (String) Inverters
A central inverter is the typical inverter that is installed with a home solar photovoltaic panel system and is closer to the size of a large home-printer. Central inverters are also called string inverters because one inverter is connected to a string of PV panels. The central inverter is usually installed at ground level or near the breaker box. String inverters are generally more cost-effective at installation, but they are best used for solar energy systems that have zero shading at all times and have panels that all face the same way. This can limit the energy production if your home has multiple roof gables or shading from trees or structures such as chimneys. A central inverter restricts the system production to the weakest panel while micro-inverters can maximize each panel’s individual production.
Additional Benefits of Micro-Inverters
Micro-inverters have longer warranties since they are not exposed to the high-heat and high power loads that central inverters are exposed to. Typically, micro-inverters have a warranty of 20-25 years which is 10-15 years longer than central inverters. Micro-inverters are also easily expandable since you won’t have to restring the entire system to add more panels later. Monitoring performance reports on a panel-by-panel basis can allow minor tweaks to individual panels to keep the system running optimally. Additionally, if something does go wrong with one of the panels or the micro-inverter attached to it, the rest of the system will continue to operate. Micro-inverters are also safer due to the lower voltage of operation and they do not require active cooling, therefore they operate without noise.
Micro-inverters are more expensive than central inverters but they have many benefits that may offset the initial cost to make them more beneficial long term. Installations with micro-inverters take less time and are less complicated which can decrease the cost of installation by 15%. Micro-inverters also have better durability and longer lifespan. It is calculate the lifetime costs and lifetime energy production of the system when evaluating the long-term usefulness of micro-inverters. Each solar project is different.
The solar experts at Action Air Conditioning, Heating and Solar will help determine if going solar is right for you. Call us at 800-400-4152 or Contact us on the web today for a FREE SOLAR QUOTE and more information!