Solar FAQ: Do Solar Panels Need Direct Sunlight?

It would be right to assume that solar panels require sunlight to work. That’s the whole concept of this form of energy, after all.

But we have to be realistic and consider that our solar panels aren’t going to be sitting in glorious, beaming direct sunlight every single hour of the day.

So, what does this mean for their energy generation? Will solar panels work if they don’t have direct sunlight or is there a bit of leeway?

If you’ve been considering solar panels but are worried about the lack of direct sunlight on your property, then all is not lost.

The truth is that while direct sunlight is always going to be preferable, solar panels will still work on an overcast day, in partial shade and without constant direct light. Of course, we also have to consider how this will affect their efficiency.

Where Should My Solar Panels be Situated?

One of the first things that your solar panel installer will discuss with you is the suitability of your property for the installation.

In terms of solar panel placement, many properties are ready to go but you’ll still need to consider where those panels are going to sit.

In the UK, having your solar panels on a south-facing roof is always going to yield the best results. This part of the roof will have the most direct sunlight throughout the day.

However, if there is a reason that you cannot place your solar panels on the south-facing roof then the next best thing is to use the east or west-facing roof. While this may mean that your solar panels are around 15-20% less efficient, they’ll still generate more than enough energy to power your home.

In some cases, neither the south or east or west-facing roof will be able to take solar panels. If this happens then I’d strongly recommend looking at alternatives because placing solar panels on a north-facing roof is never a great idea. This part of your home will receive the least sunlight so it usually isn’t viable.

That said, there may be some situations in which correct orientation and a lack of items that cast a shadow could improve the viability of a north-facing roof for solar panels. But this is something you’ll need to discuss with your installer.

What About The Weather? Will Clouds Affect My Solar Panels?

When it comes to direct sunlight, the UK doesn’t get too much of it and it seems that we face more overcast days than not.

So, what does this mean for your solar panels and their ability to generate power?

Well, it’s good news because your solar panels will still work on a cloudy day, albeit they may not produce quite as much energy. However, UK homeowners still find that solar energy is an efficient and reliable way to power their homes.

It’s really important to remember that, just because there are clouds in the way, the UV rays produced by the sun are powerful enough to penetrate them.

Will Shade Affect My Solar Panels?

It’s always best to place your solar panels in a location where they’ll receive as much direct sunlight as possible. However, there are plenty of examples of properties for which, no matter where you place the panels, some shade is inevitable.

The key is to think about how that shade will move during the day. As the sun moves, so do the shadows so it’s unlikely that a well-placed panel will be in shade all day.

For example, if you have a tree that shades your roof during the morning, you may find that, once that shadow has moved, your panels get more than enough sunlight during the afternoon.

Of course, if the selection location for the solar panel is in shade all day then it’s probably a good idea to reconsider. While indirect sunlight will still generate energy, you can expect shaded panels to be just half as efficient as those placed in full sun.

How Much Direct Sunlight Do Solar Panels Need?

As I have just discussed, solar panels can sit in shade for part of the day and still generate enough energy to power your home. So comes the question of just how much sun do they need every day?

The more sun the better as this will boost the efficiency of your solar panels but realistically, there’s always going to be some kind of shade, cloud or other hindrance. 

But the good news is that experts, like us, recommend that solar panels have just four hours of direct sunlight per day to operate at maximum efficiency. That’s excellent news when you live in a country where clouds are pretty much a given on most days.

Should I Get Solar Panels?

Making the decision as to whether installing solar panels is worth it, many people think about how efficient the panels would be. This often comes down to looking at how much sunlight the panels will realistically get each day.

There’s a common misconception that solar panels need constant direct sunlight to work. Yes, if they sit in continued direct sunlight, they’re going to work more optimally than if they’re in the shade all day. But solar panels placed in partial shade or under a cloudy sky will still produce power.

It’s incredibly important to consider the factors I’ve discussed in this post and talk through your solar panel placement options with your installer. This way, you can ensure maximum power output regardless of whether the panels experience direct sunlight.

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