If one type of solar panel has a higher efficiency rating than another type, you probably won’t need to buy as many of them (or use as much surface area) to power your house or business.

No, it isn’t. While solar panel efficiency is an important factor to consider when looking at installing solar panels, other important factors include the:

• price of the panels
• available space on your roof

You may find a solar panel that is, say, 1-5% more efficient than another panel but costs almost twice as much. In this case, if you have ample space on your roof for the panels, efficiency is unlikely to be the deciding factor in what solar panels you purchase.

In other words, instead of asking ‘Which solar panels the most efficient?’, you’re better off asking ‘Which panels are the best value for money?

It’s important not to get too caught up in solar panel efficiency, as there are several other factors that affect the overall power output of panels—which, let’s face it, is the main concern for home- and business-owners trying to cover their power usage and minimise their bills.

Most of the factors that affect the overall power output of solar panels have to do with available light. These include:

• the size of the panels
• the total number of panels
• whether there is dust on the panels (this reduces the amount of light)
• where the panels are placed on your roof (their orientation)
• the angle of your roof structure (often called the ‘pitch’ or ‘tilt’ of your roof)
• how hot the panels get (solar panels love sun, but like the rest of us they don’t like too much, and they appreciate a breeze. If they get too hot their efficiency can actually decrease)
• shade (obviously, shade will decrease power production. In fact, some solar panel systems will shut down if even one panel is in shade—akin to one fairy light in a string not working and causing the rest of the section to fail)