If your system has been installed for several years and you don’t have modern monitoring installed, you may be in the dark about whether your solar system has been working well over the years. This is a common question that we get asked here at SkyGreen, most often about ‘orphan’ systems that were installed by companies that are no longer in existence.

People also find themselves misled by their energy bills, which actually do not reflect properly the operation of the solar system. This is because the bill, which is informed by your electricity meter, only sees the amount of solar that goes back to the grid. It does not see the amount of solar that powers the home directly; your home is drawing solar energy. This energy, called “self-use” is invisible to the meter and, therefore, unmeasured by your meter. You will likely have experienced large benefits from the solar self-use, realized by lower power consumption and bills, even though you will not find an amount of savings listed on your bills anywhere for that. (Installing modern ‘consumption metering’ will do this for you).

What to do, then?

Most older solar inverters have a screen showing basic information. A typical inverter from several years back should have a reading called E-total or Total kWh. Perhaps it says 26,280 kWh. From here; how long has the system been installed for? And what is its daily expected generation? [You will need to consult your original quotation for this estimate].

If your system has been installed for 9 years, then your system has been operating for 3285 days. Divided into 26,280 gives 8 kWh per day. This is what it has been generating. How does this compare to the initial quotation? If it’s, say, within 10% to 20% then I would be happy. It usually is, if everything has been going well. If the system has been working noticeably worse, there has probably been a problem with it, and the system should be inspected. SkyGreen offers this service.