If you’re making the switch to solar energy, then chances are that you’re interested in being more energy efficient and shrinking your carbon footprint. But if you thought that switching to solar panels was all you needed to do, then you were mistaken!
The fact of the matter is that solar panels themselves can also be made more or less efficient, helping you to save more or less energy on your regular bill, depending on a number of factors. One of these factors is the precise angle of the panels themselves.
In this post, we will look at why the angle matters so much when using solar panels and how you can work out what the best angle for solar panel energy is for you (yep, it varies!).
Why the Solar Panel Angle Matters?
There are two kinds of solar panels that that are used in residential settings.
One of these is solar thermal. Solar thermal panels work by using networks of tiny tubes filled with water across the surface of the panels. These tubes hold the water in the view of the sun, which causes the water to heat up – which creates energy.
Generally, this heat energy will be relatively minor and it won’t be converted into any other kind of energy to run appliances etc. Therefore, this form of solar energy is typically best suited to being used for heating applications. You’ll often find this being used to heat small rooms for instance, or to heat outdoor pools (though geothermal methods might be more appropriate for this!).
Solar thermal panels need to be angled so that they get as much sunlight as possible. But seeing as they don’t require the light specifically, it’s not the end of the world if they aren’t directly in view of the sun – as long as the water gets heated!
But this is not how the majority of solar panels work. The majority of solar panels used for applications around the home instead use a method called solar photovoltaic. This uses a smart arrangement of electrons that gets excited when exposed directly to sun light. In this case, it is all about the light and not about the heat, which in turn means that it is highly important that the panels be positioned to directly receive the light.
This is the type of solar panel that is used to power appliances in the home, that generates electricity for you to sell back to the grid and that might make you eligible for tax rebates. But it’s also a big investment. An array (group) of solar panels attached to your roof for instance can cost you thousands of dollars and take years to break even. For that reason, you need to understand the optimal angle and think very carefully about where you place your panels and whether your home is even suitable for them.
But It’s Not That Simple
Great, so all you need to do is to put your solar panel at the precise right angle and be done with it, right?
Unfortunately, it is not that simple. The best solar panel angle is dependent on a number of different factors.
The problem is that the sun will spend most of its time high in the sky. So, if your solar panels are facing mainly forward, then they aren’t going to be getting the majority of the light, the majority of the time.
In a perfect world, you would track the sun as it moves across the sky. This is actually possible with tracking solar panels, also sometimes known as ‘active’ solar panels. These are programmed to change the angle of the solar panel throughout the day, so that it will follow the precise trajectory of the sun as it moves. Of course, this can greatly improve the amount of time that your panels spend directly pointing at the sun and can greatly improve the amount of energy you get from your panels.
So why doesn’t everyone use tracking/active solar panels and be done with it? The answer is pretty simple: active trackers are very expensive. And to set them up for an entire array would likely cost so much money as to make it hard to earn back that investment for a long period of time.
Of course you could head out and manually adjust your solar panels on a regular basis, but this would be a time consuming process and again, the benefits might not be worth it for many people. You could always head out a few times during the day, but again, this is going to be a time consuming process.
So, most panels are going to be on a fixed mount and in a single position for half or a quarter of the year at the time.
Ideally, you want your panel to be positioned so that it will be in the optimal position to receive the sun when it is at its brightest and so that it will be visible for the longest time possible. This means you need to consider both the angle that your panel is facing, as well as the precise angle of the tilt – how directly upwards is it pointing?
How to Calculate Your Angle?
The first complication, is that the optimal position is going to vary dependent on your location. If you live in a northern hemisphere, then you will need to point your panels due south. For those in the southern hemisphere however, panels need to point north.
From here, you then need to calculate the perfect angle for your tilt. There are a few ‘quick and dirty’ ways to do this. One way to get the best angle for solar panels or close enough, is:
- Take the latitude
- Add 15 degrees for the winter
- Subtract 15 degrees for the summer
So, if you were to say that your latitude was 40 degrees, then you would tilt your panels 40 +15 to 55 degrees during the winter. Then in the summer, you would tilt it the opposite way. This will mean 40 – 15, putting your angle at 25 degrees.
In both cases, your panel will be pointing largely upwards but not directly into the sky.
There is a better option though for both the winter and the summer.
For the winter, when there is less sun available for your panels, you can try taking your latitude and multiplying it by 0.9, before adding 29 degrees.
So: (Latitude X 0.9) + 29
This will usually give you a slightly steeper (~10 degrees) angle than the ‘fast and dirty’ method. It will be facing the sun more directly during mid day, which is useful in those shorter winter days.
In the summer, the equivalent method will be to take the latitude, multiply by 0.9 and then subtract 23.5 degrees.
So: (Latitude x 0.9) – 23.5
This means that if you have a latitude of 40 degrees, the panels will end up tilted to 12.5 degrees. It’s a little complicated but if you have a calculator to hand, you can figure it out once, write it down and pin it somewhere easy to see!
If you want to be really conscientious, then you can also move your panels again during spring and fall. In this case, you will take the latitude and subtract 2.5 degrees. That means you’ll be tilting your solar panel a total of four times per year.
But of course this all depends on your needs. While it’s ideal to generate as much energy as possible, you might find that if you have a specific need in mind (powering a particular appliance for instance) and you aren’t selling energy back to the grid, that you can manage just fine with your angle set to a single position.
If your solar panels don’t create enough energy, then you won’t have the option to sell that energy back. And because most arrays for the home don’t have any means to store energy, there’s actually no benefit in that case to keeping your panels moving. You may as well just leave them as is if they’re generating enough for your needs! Then again though, if your solar panel is attached to a solar generator and powering a battery, then this makes it more sensible to keep them moving. The same goes for solar panels that power multiple appliances in your home if you want to maybe get one more thing running off renewable energy.
Keep in mind that panels that are fixed are actually most efficient during the winter months. That’s because the sun moves in the sky less during this time!
And note that the very best way to calculate the best angle for solar panels, is to use a solar panel calculator. This will give you a more accurate number based on the precise time of year and your exact location! These area very handy tools that can save you from doing all of this!
Note that these calculators can have other uses too. For instance, if you’re going to be using a portable solar generator while you’re out camping, you can use the calculator to quickly look up the best place to put your generator and thereby charge it more quickly and gain more energy for your phones, laptops and cooking appliances.
Ah, if only it were all that simple though!
It would be great to simply change the angle of your solar panel and be done with it, but there are lots more considerations to take into account and these can all impact on your efficiency.
For starters, you might find that the direction and angle of the roof impacts on your available options. It’s find to say that you should face your solar panels North and tilt them at a 45 degree angle, but if you have a very sloped roof that points East and West, what do you do?
You will have the option to change the angle by altering the position of the mount for your solar panels and this will somewhat counteract an uncooperative roof. But there is only so far this will work, as after a point your solar panel array will begin to cast shadows on itself.
Another consideration is shade. You can have your solar panel in the perfect angle and in pointing in the ideal direction… but if they area under the shadow of a big tree or another building, then there is really no point in having them at all!
This can once again be an issue for arrays that are placed on the roof, if your building is overlooked by another larger building, or if your building is underneath a large tree that isn’t yours. This is why you should have someone come round to check your premises before you invest in solar panels. Most companies and local governments will insist on sending someone round before your installation – if this doesn’t happen, then you should insist!
Of course shade might play a more minor role. For instance, if your solar panels are going to be in slight shade, then this might impact on the optimal direction and angle of your panels. It may be that what would otherwise be considered the ‘perfect angle’ actually means your panel is only pointing at the sun when it is in shade. If you change the angle slightly, then during that time of year you might catch the sun for a little once it has moved out of the unfortunate position.
You should think carefully about all these factors before you consider investing in a solar panel set-up. You need to look into whether or not your home is a suitable option for a solar panel array of any kind and you need to decide where the best place for it is. In some scenarios, your array may work better in the garden but of course that is less likely as it will be lower to the ground. Of course you also need to think carefully about just how much ground you are going to be giving up in order to enjoy that solar energy.
Angles for Other Solar Powered Products
But of course your solar energy isn’t just about replacing your energy bill! Solar has been around for a long time now, used to power a wide variety of smaller garden features. You need to think about these too when considering the best position at different times of day.
Perhaps the most useful and straightforward solar powered product on the market is the solar powered garden light. These are lights that you simply stab into the grass outside, or place around your garden, in order to keep the space lit in an atmospheric way. The great benefit of solar lights over other lights though of course is that they don’t need to be plugged in and don’t require batteries. Instead they have solar panels that allow them to charge during the day so that they always have plenty of power when it gets dark.
You should be able to generate enough power wherever your lights are in the garden, just make sure that the panels are facing vaguely upwards and that they aren’t in shade!
As well as garden lights, there are many other kinds of solar powered lights you can buy too – such as burglar lights designed to come on when they detect motion thus hopefully scaring away any potential trespassers or lighting the front garden for you when you come home. These might have more visible panels attached to the top and it can be useful to consider the angle of these panels and to make sure that they aren’t in the shade.
Likewise, you can also find solar powered fountains and even moving decorations. If you use these within the home, then you will need to keep them in the window. In which case, it can be useful to consider which windows in your home will get the most light at different times of day and different times of the year.
Using solar power for your lights alone though isn’t going to save you all that much money – these days it’s our countless electronic gadgets and devices that are the most power-hungry. Fortunately, these can benefit from solar power too if you get yourself a solar charger. These essentially allow you to charge your devices outside as long as the sun is out, meaning that you can avoid plugging your phone or tablet into the mains quite so often. This is also a very handy thing to have when travelling in case power outlets are tough to come by.
And there you go. You now have a complete understanding of how to get the most from your solar powered lights and what the best position, angle and tips are to ensure that you will maximize your investment and minimize that footprint!