• Save 70% On Average On Your Electricity Bills
  • Accredited Installation Teams
  • Expert Advisors Ready To Help You

How efficient are solar panels?

"*" indicates required fields

This field is for validation purposes and should be left unchanged.

  • Save 70% on average on your electricity bills
  • Expert advisors with decades of experience
  • Partner with Growatt, the No. 1 global supplier
gsl van

Whether you’re looking to cut down on your energy bills, or just want to do your bit for planet earth, more people are opting for solar panels as a clean and sustainable energy solution. But just how efficient are solar panels? Well, to answer that question, you have to get into the details. This includes:

  • The different types of solar panels and their efficiency
  • What affects a solar panel’s efficiency
  • How solar panels’ efficiency changes over time

But before we get into all that…

What does solar panel efficiency mean?

Solar panel efficiency refers to how effectively a panel can convert sunlight into usable electricity. Efficiency is shown as a percentage, representing the portion of solar energy the panel can convert. The higher the efficiency, the greater the energy output, making efficient solar panels highly sought after. 

What are the most efficient types of solar panels?

There are many different types of solar panels, each with their own advantages and drawbacks. The type of solar cell you choose will determine how efficient your panel is. 

Monocrystalline solar panels

These are made from a single crystal structure and, while they tend to be more expensive, usually have higher efficiency rates.

Polycrystalline solar panels

These panels are made up of multiple silicone crystals, meaning the space between the crystals can’t convert sunlight. While these are less efficient, they can be a more cost effective option. 

What affects a solar panel’s efficiency?

Several factors influence the efficiency of solar panels. While the quality of the materials and construction is an important factor, how you look after the panels matters just as much. 


A small amount of shade can have a big impact on a solar panel’s efficiency. Some reports suggest that if just 10% of the panel is in shade, it can be up to 50% less efficient, so make sure you put yours in a sunny spot.

Panel placement

You know how everyone is after a south facing garden? So are solar panels. If you don’t have a south facing garden, install your panels on the south side of your house. This will expose them to more sun, making them more efficient. 


We all know things don’t work the same when they’re too hot, whether it’s your phone, laptop or car. Well, it’s the same for solar panels. While they are designed to convert sunlight into electricity, if their temperature rises too much it wont work as effectively. This shouldn’t be a problem in the UK, however, as our summers tend to stay at a mild temperature. 

Roof pitch

The angle you install your solar panels at can affect how much sunlight it receives per day. For domestic solar panels in the UK, the best pitch is around 30 to 45 degrees. 


Don’t be fooled into thinking the rain will keep your solar panels spotless. Occasionally, you will have to give them a deeper clean to get rid of bird droppings, dirt or leaves that may have collected over time. The cleaner it is, the better it works. 

Do solar panels become less efficient over time?

Over the lifespan of a solar panel, its efficiency gradually decreases due to various factors. One significant factor is the natural degradation of materials, including the wear and tear on semiconductor cells. However, reputable manufacturers typically provide warranties guaranteeing that solar panels will maintain a certain level of efficiency for a specified period.

So, now you’ve done the research, you just need to decide which type of solar panel you want and get it installed. That’s where Grant Store comes in. With a range of Solar PV packages and helpful finance options available, our experts are on hand to help. Get in touch today to start your solar panel journey.

Did you know we can also help you secure free solar panels?