Solar FAQ: How Efficient Are Solar Panels?

Back when solar panels first became popular among domestic property owners, there was one major problem that hung over everyone’s heads – That is, efficiency.

I’ve spoken to many people who assume that solar technology has not advanced at all in the last couple of decades. As such, they’re under the assumption that solar panels are nowhere near efficient enough to power a home.

But this couldn’t be further from the truth. In fact, solar tech has advanced so much that it’s more than possible to run a home on solar power.

What Is Solar Panel Efficiency?

When we talk about solar panel efficiency, we’re referring to the amount of sunlight that any given panel can convert to usable energy.

Back in the day, solar panels may have only been around 15% efficient but modern advances mean that even bog-standard solar panels may boast efficiency of up to 20%.

And it doesn’t end there. Some of the more high-powered solar panels have a standard efficiency of around 23%.

I’ve even read reports of some solar panels performing up to 42% but it’s important to remember that this is recorded during lab testing. While this is certainly impressive, you may find that they don’t perform quite this well once they’re on your roof.

What’s The Most Efficient Type Of Solar Panel?

In the UK, there are three main types of solar panels used by installers. Monocrystalline solar panels are generally accepted as being the most efficient. As such, they’re the typical option for most installers who will recommend them to domestic buyers.

However, it’s also worth keeping in mind that polycrystalline and thin-film panels both have their role to play.

For starters, while considered the least efficient, thin-film panels are far more affordable so, if you’re looking to dip your toe in the sustainable energy market without spending a fortune, this might be worth considering.

On the other hand, polycrystalline panels are only slightly less efficient than their monocrystalline counterparts. Where monocrystalline panels generally have a 20% efficiency, polycrystalline comes in somewhere between 13 and 15%.

They’re also larger and more affordable than monocrystalline which can be attractive to homeowners.

What Affects Solar Panel Efficiency?

The type of solar panel you install will play a significant role in the efficiency of your green home. However, this isn’t the only factor that you need to consider.

Even the most powerful and efficient solar panels will only produce the expected amount of energy when properly placed. Solar panel orientation is incredibly important and, generally speaking, you’ll want to place your panels on a south facing roof for the greatest efficiency. While east and west facing roofs are acceptable, using them for your solar panels could decrease efficiency by up to 20%.

The angle of your roof also contributes to the efficiency of your solar panels. Most experts agree that the ideal roof angle in the UK is between 30 and 45 degrees. Anything outside of this variation and you may notice a drop in panel efficiency.

You should also consider that the weather plays a huge role in how much energy any individual solar panel can produce.

I recently wrote a post about whether solar panels will work on cloudy days and it’s evident that they do. However, when they aren’t in direct sunlight, this will decrease the amount of energy they can produce. Compared to a bright, clear day, your solar panels may become between 10 and 25% less efficient when the sky is overcast.

Similarly, efficiency is also affected when the solar panels don’t receive as much direct sunlight. This could be because of shade cover for part of the day, during the winter when the sun is not out for as long nor as strong etc.

Finally, you must ensure that your solar panels are well maintained. Poorly maintained solar panels will suffer from a build up or dirt and debris that can hinder their potential. Regular solar panel cleaning (around once every six months) will help to ensure this doesn’t happen. It’s also important to check your solar panels for signs of damage and have any problems fixed by a professional installer as soon as possible.

Are Solar Panels Efficient Enough To Fully Power My Home?

With fossil fuel supplies running low and more people becoming aware of the damage burning these fuels can do to the environment, more homeowners are looking at using a green energy source.

What could be more eco-friendly than the very light in our skies?

This all sounds great but many people are concerned that solar power won’t be enough for all of their energy needs.

I won’t lie, most people choose to supplement their grid supply with solar, using both but saving on their energy bills by harnessing the power of the sun.

But that doesn’t mean it isn’t possible to fully power your house using solar panels. In fact, a lot of eco-warriors are already doing this.

What you do have to consider, however, is that in order to fully power your home using solar, you will likely need a greater number of more powerful panels. While this may require more planning and a larger investment, the savings over time will be seriously impressive.

Do Solar Panels Lose Efficiency?

Solar panels are designed to last for a very long time. In fact, most manufacturers will provide you with a warranty that lasts between 10 and 20 years.

Normally, you can expect a solar panel to have a life of around 25 years although there are some that could continue performing for as long as 30 to 40 years. It all depends on the quality of the panel and how well-maintained it has been.

But, despite their amazing longevity, solar panels, like anything else, will eventually need to be replaced. Over time, wear and tear, often caused by UV rays, will cause the panels to lose efficiency.

It’s estimated that a solar panel will lose around 0.5% efficiency every year. This means that, after two decades, it’ll only perform at 90% of what it did when it was brand new. But I still think that’s pretty impressive for something that’s been working hard for twenty years!

As I mentioned earlier, good maintenance will ensure that your solar panels have as long a life as possible and perform as efficiently for as long as possible.

Request a call back

* Required Fields

We hate SPAM and we promise to keep your email address safe. Here are our Terms & Conditions.

By clicking on the link, you are agreeing to go on our mailing list. You can unsubscribe at any time.