The Best Angle For Solar Panels: How to Get Every Last Drop of Energy
Updated: Oct 3, 2018
When you install solar panels, you want to have as much sun hit the panels as possible. But setting the right angle so they catch enough sun to maximize output can be confusing. So how do you calculate the best angle for solar panels and how do you know it's the right one? Let's dive in and find out.
What is so Important about Tilt Angles?
To start off, let's talk about the importance of tilt angles. Having your solar panels tilted at the right angle ensures that when the sun is at its peak, the panel can maximize its energy generation.
If your panel is lying on a flat roof without being tilted, for example, then it will only receive half of what it could get (and its harder to clean). However, with it tilted even a bit, your panel can get the full force of the sun.
In the U.S., with exception of a couple regional differences, most roofs are built to slope at 30-degrees. When installing a solar system, this is usually enough to get as much energy as you can with a fixed model.
In arid climates though, many roofs are built flat, so extra hardware is needed to fix the panels at the right angle. In snowy, northern climates, some roofs are pitched more sharply, around 40-45-degrees which is also perfectly fine.
While it is more cost-effective and efficient to fix your panels parallel to your roof, knowing the slope angle of your roof will determine if you need extra hardware or not.
Other Variables to Look For
When you are trying to find the right angle, there's other variables besides slope of rooftops to look at. In northern hemispheres, south-facing roofs tend to get more sun throughout the day. Due to this, installations will typically use the south-facing side of roofs rather than west or east.
There has been some debate over whether east-west facing roofs should be preferred. Since the sun rises in the east and sets in the west, panels installed facing east-west are always getting sun as well.
Based on this, while a south-facing roof is preferred and usually where installation occurs, an east-west facing roof will work just as well. In fact, some people have used south-facing and east-west facing roofs so they get the most energy output available to them.
Know Your Latitudes and Figure Your Angles
Another variable of figuring out where exactly your panels should be is knowing geographically where you're at. For example, two large cities on the Eastern seaboard will have slightly different latitudes. Even five degrees can change how much energy you're receiving.
Knowing what your house's latitude is will help you determine how far to tilt your panels. So if you live in New York City, the perfect tilt angle is 42-degrees. Key West, FL, the latitude is 24, so the perfect tilt angle is 24-degrees.
Here's why this works. As the seasons change, how close the sun is to the Earth changes. In winter, it's closer; summer, it's further away. Where you live changes this too. The lower your latitude, the higher the sun is all year. However, your solar company will figure this out for you so you don't need to worry about calculations.
Something to consider though: using the latitude is only useful in certain situations. While it will give you a good estimate of what the best angle to maximize your energy will be, simply using the pitch of your roof will often suffice. This video explains the idea better, but you will only lose a small percentage of energy in the long run.
Seasonal Changes: Using Adjustable and Tracking Panels
So far, we've been focusing on how to find the right tilt angle for fixed solar panels. Fixed panels are what most people buy because they're more cost-effective and work well.
However, if you want to ensure you get the most energy through the seasons, you can have your solar panels installed with an adjustable rack. Then twice a year, you can tilt your panels to adjust for summer and winter.
Since the position of the sun changes with the season, having adjustable panels can increase your energy output by up to 5%. It's not much, but the savings do add up over time.
By default, you should adjust your panels 15-degrees steeper in the winter and 15-degrees lower in the summer. If you want to be a little more exact in the math, this site has formulas to help determine how much you can adjust your panels.
Tracking panels are another solution if you want to gain the most energy output throughout the day. As you can probably guess from the name, tracking panels track the path of the sun throughout the day. Single-axis trackers have a much better energy output than fixed panels systems.
However, there's several drawbacks to tracking panels. One, they have to be mounted on level ground. For people who don't have a lot of backyard space or even level enough ground, this is not a viable option.
Second, while they can withstand wind-speeds of up to 135 mph, the modules in the panels close off around 60 mph. So if you live in a place where the wind is constantly blowing hard and steady, you won't get a lot of good use out of it. In that case, you may want to consider harnessing wind energy instead.
Finally, they can be hard to maintain for 25 years. Think about it, all the motors, gears, and small parts it takes to move and track the path of the sun wear down over time. Something can easily break or malfunction and then your whole system is down.
Similar reasons can be attached to adjustable panels. While they can be mounted on the roof, they need more space in between them so they aren't casting shadows on the panel behind them. So while you can fit 20 fixed solar panels on a 300 square foot roof, you can't do the same for adjustable panels.
In some of the ways described above, the cost-benefit of adjustable and tracking systems aren't much more than fixed panel systems. While they can improve your output and save you a little more money on energy bills, it costs more to install them properly and more work goes into the upkeep and keeping them adjusted correctly. For the average home, the energy savings aren't enough to offset the cost of tracking and adjustable systems.
To Wrap it Up
In order to maximize your solar energy output there are several things you can do:
Learn and understand how the angle of your panels can affect your energy output.
Know what the slope of your roof is; the most common angle is 30-degrees, but some roofs can be flatter or steeper regionally.
South-facing roofs are preferable for installation in North America but having an east/west facing roof can work just as well.
The latitude of your home is considered in panel placement. But using the pitch of your roof is more cost-effective than investing in tilt racks.
Adjustable panels can be installed to improve energy output by adjusting 15-degrees steeper or lower according to the season. But most of the time this isn't a large improvement and therefore isn't necessary.
While both tracking and adjustable mounts can improve energy output, neither are as cost-effective as fixed solar panels.
Was there anything we missed or anything can be cleared up? Do you have advice on how to get the best angle for solar panels? If you do, comment below and let us know!