Solar PV Inverters: “Is it working properly?” If not, you could be losing out on Hundreds of Pounds!

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Solar PV Inverters

Have you checked the display panel on your Inverter lately? If the Inverter has occurred a fault, or is broken then you may be losing out on hundreds, or even thousands of pounds. We have recently attended a significant number of call-outs to find that the inverters have stopped working and in need of repair or replacement.

An inverter is a system which inverts (changes) the energy that your solar panels pick up from the sun, the direct current (DC), into alternating current (AC). AC is the current of electricity that can be used directly by your appliances or can go straight back onto the grid to be used by others.

Inverters also monitor the amount of electricity being received and outputted so that you can keep an eye on the efficiency of your panels and how much energy you are producing.



String Inverters

The traditional inverter is a string inverter, typically a box which is housed in the attic. Cables run from all the solar panels into the box, where inversion takes place. String inverters are currently the most tested and most reliable.

However, string inverters do have some issues. If one of your solar panels is shaded or damaged, and therefore working at a lower efficiency, then the overall output from the inverter may be reduced. Imagine a string of fairy lights, when one individual bulb is not working then none of the lights will work, string inverters can act similarly.

Micro Inverters
The newer type of inverter is called a micro inverter. Micro inverters are small boxes situated behind each individual solar panel that invert the sunlight into AC current directly at the panel. Micro inverters solve a lot of the issues found in string inverters. If one panel is not performing optimally it become obvious which panel has the issue and the overall output is not affected. They also have a longer life and up to 25 year warranties. However, as they are a newer technology, they are not yet as advanced or widely available as string inverters.

Cost and Lifespan

The cost of your initial inverter and the installation should be included in the quote given by your solar panel installer. However, as solar panels have such a long-life span, inverters currently are unlikely to last the same amount of time as your panels. Most string inverters come with a 10-12 year warranty, compared to the 25 year warranty of most solar panels, meaning you will probably have to replace them at some point. Your installer can offer you information on which is the best inverter and which ones they use.

Which inverter you will need depends on the size of your system. Inverters vary a great deal in price but it will be around £500- £1000 for a new string inverter on an average residential property. This price may seem high but it will easily be absorbed into the continued energy bill savings that the inverter will generate.

It is harder to determine a definite price for micro inverters because it will depend on how many individual solar panels you have and what size the system is. Average prices range from about £60 – £90 per micro inverter box. Some companies offer packages for common system sizes. Therefore, a 4kW pack with additional accessories could be around £1500 for 16 inverter boxes. If you have less solar panels then the price will be much less.


As it stands string inverters are most efficient. This is because they have been around for a very long time and have therefore been researched and improved to provide maximum efficiency.

However, micro inverters could be the solution to many of the problems unsolved by string inverters. Currently string inverters do not get the maximum efficiency from each solar panel and if one solar panel is not performing well it can bring down the amount of electricity generated from the whole system.

As micro inverters are still relatively new there’s lots of room for improvement with how they operate. They are also still a fairly pricey technology; however their long-life span may justify the cost. Most installers are still using string inverter systems as standard. This could change very soon as micro inverter systems become more efficient and cheaper to purchase.


Ask the company which type of inverter they use and whether you have the choice of a string or micro inverter, try finding out the brand and doing a bit of research. Currently string inverters are the more stable choice but micro inverter technology is rapidly improving.

String inverters have generally have a lifespan between 10-15 years, a lot shorter than the potential life of your solar panels which can be as much as 25 Years. Therefore, you should look ahead to decide whether you would like to replace your inverter with another string model or if you would like to invest in a new, longer lasting, micro technology. As micro inverters continue to become more efficient and cheaper, they could very well become the standard in solar PV systems very soon.

If you are experiencing problems, or you’re unsure if your panels are working correctly then please don’t hesitate to contact us.

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