If you are considering installing solar panels on your home, you undoubtedly want to get the most clean energy you can from them. Therefore, the proper solar panel tilt angle is an important consideration. We are dedicated to installing solar systems with excellent energy production for decades at Smart Solar Energy, so we take optimum solar system design seriously.
However, there isn’t an ideal angle for all homes because it varies by the property, location, and aesthetic preference. Let’s examine how we select the ideal tilt angle for solar systems in Oregon and Washington.
Why do we mount solar panels at an angle?
Your rooftop solar system will generate the most renewable energy if mounted at an angle perpendicular to the sun. So, the ideal year-round angle for solar panels is the latitude of your property. This is because your latitude impacts the angle at which the sun hits your rooftop.
But the angle of the sun varies throughout the year. Therefore, there is an ideal winter angle and an ideal summer angle for solar panels. The ideal summer angle is lower than the optimum winter angle because the sun is higher in the sky in the summer. Yet most solar panels are installed at a fixed angle, especially when mounted on a sloped roof.
How do you calculate the ideal angle for solar panels in Oregon and Washington?
At Smart Solar Energy, we consider numerous factors when deciding on the solar panel tilt angle. One important factor is the latitude of your property because that impacts the angle that sunlight hits the PV panels.
A property that is further north will generate more solar electricity if the panels are mounted at a steeper angle. By contrast, homes that are further south benefit from a lower tilt. At Smart Solar Energy, we specialize in solar systems in Oregon and Washington, so we usually mount panels at a relatively steep angle.
Because Washington is further north than Oregon, a higher tilt angle is better from an energy production standpoint. This is evident when looking at the chart below.
Ideal solar panel tilt angle for in Oregon:
Ideal year-round angle for solar panels
Ideal solar panel tilt angle for in Washington:
Ideal year-round angle for solar panels
However, the tilt angle is not the only consideration. Most homeowners like the look of solar panels mounted flush against a pitched roof because they blend well. Also, these solar systems tend to cost a bit less because they require less hardware on the roof and less time to install them. Therefore, most solar panels are flush mounted on roofs when they have pitched roofs.
If you live in an area with a homeowners association or condominium association, they may have restrictions on how you mount your solar panels. For example, they may specify that solar PV panels are flush against the roof in their covenants, conditions, and restrictions.
Another consideration is snow. If you live in an area of Washington or Oregon, like Mount Rainier or Mount Baker, that gets a lot of snow, a steeper angle is preferable. A steep tilt allows the snow to slide off the solar panels more easily, boosting winter solar energy output.
Does longitude impact the ideal angle of solar panels?
No, the longitude of your solar system doesn’t impact the ideal angle, just the latitude. For example, Bend is east of Eugene, but the ideal angle is the same because they have similar latitudes. Likewise, Spokane is east of Seattle, but they have the same ideal angle because they share similar latitudes.
Why are most solar systems flush mounted on sloped roofs?
There are numerous advantages of having your solar system flush against your roof with just a little gap for airflow. The total cost of installing a solar system is usually lower when mounting them flush against the roof instead of tilting them up above the roof’s plane. This is because additional solar racking hardware is needed, and it takes longer for solar installers to assemble the additional hardware.
In addition, compound mounts have greater wind load because they can act like sails in windy weather. Therefore, more work is needed to properly engineer the system to ensure it is safe and structurally sound.
Likewise, your local permitting department likely has more restrictions on compound mounts, complicating the permitting process and potentially slowing it down. However, we take care of solar system permitting on your behalf at Smart Solar Energy.
The final consideration is aesthetics. Most Smart Solar Energy customers prefer the look of solar panels when they hug the roof because they blend well. Also, if you end up selling your home, homebuyers will likely also prefer the look of a flush-mounted solar system. We can also install all-black solar panels that blend well with your roof that do not have a silver frame or backsheet. These solar panels have a sleek look and are very popular.
We like to leave a small gap between your roof and the solar PV panels. This helps boost the efficiency of your solar power system because the modules perform better below 77 degrees Fahrenheit. Leaving an air gap between your roof and the solar panels allows ventilation for the air to cool off the solar panels during the dog days of summer. If the air gap is too small, the PV panels will heat up too much and have lower solar energy output.
Does it matter what direction my solar panels face?
Yes, it is best to orient your solar system so that it faces south because Oregon and Washington are in the Northern Hemisphere. Conversely, if you live in Australia or Argentina, you’d want to orient your panels facing north instead of south.
However, if your house isn’t aligned with the ideal azimuth, facing the panels southwest, southeast, or even east or west could work. If you have enough space, you’ll probably want to add a couple of extra panels if your roof faces east or west. However, we do not recommend facing your solar PV panels north because it will dramatically lower your renewable energy production.
In some cases, the ideal location to mount your solar panels might be on a garage or barn roof, especially if the house roof is shaded or doesn’t face the ideal location. During your Free On-Site Solar Audit, one of our solar energy experts will design your solar system to optimize solar energy production by taking numerous factors into account, including shading, tilt angle, orientation, project budget, and aesthetic preference.
Should I get a tracking system for my solar panels?
Some solar systems have a tracking system that follows the sun to boost electricity generation. However, adding moving parts to a solar system increases the maintenance costs. Likewise, tracking systems are usually installed on poles on the ground, so it takes up yard space to install one. Therefore, we rarely recommend tracking systems on solar panels.
It is usually cheaper and more cost-effective not to install solar trackers. However, if space allows, we can add a couple of extra solar panels to boost the total solar electricity output.
How do I calculate the ideal winter and summer angle for a solar system?
Because the sun is higher in the sky in the summer than in the winter, there are different ideal angles in the winter and summer. The optimum winter angle is 15° greater than the best year-round angle. For example, the ideal year-round angle of a solar system in Portland, Oregon, is 46°. Therefore, the best winter angle for a solar system is 15° + 46° = 61°.
Simply subtract 15° from the optimum year-round angle to calculate the ideal summer angle. So for Vancouver, Washington, it would be 46° – 15° = 31°
We usually use the ideal year-round angle because you want your solar energy system to perform well throughout the year. Because Oregon and Washington have net metering programs, utility companies compensate solar system owners for surplus power they supply to the power grid. Thus, our customers can save up solar energy credits for other seasons.
For example, if you use more electricity in your home in the winter than in the summer due to your heating system, your utility provider will apply surplus solar credits from the summer to offset your winter energy bills. Therefore, we usually strive to optimize total solar energy output and not prioritize a specific season, even if your energy use is greater during certain months.
How should I mount my solar panels if I don’t have a roof with a steep slope?
If your roof has a shallow pitch, the angle of your solar system depends on your personal preference. For example, you can have the solar panels mounted at a steeper angle than the roof, but this influences the look of the solar system. Although the tilt angle of the solar panels is important, 5 or 10° doesn’t make a huge difference in energy production.
However, if you have a flat roof, the solar panels probably aren’t visible from the ground unless your home only has one story. For flat roofs, we usually recommend using a racking system and mounting the solar panels at the ideal angle for energy production.
Should I install solar panels if I need to replace my roof?
If your roof needs to be replaced soon, we recommend doing that before installing solar panels. If you need to do major work on your roof, it is necessary to temporarily remove the solar panels. Solar panel systems are designed to last for around 30 years, which is longer than the lifespan of most roofs.
One exception is metal roofs, which have been gaining popularity in Washington and Oregon recently because they perform well in our climate. Also, metal roofs are recyclable and typically last 40 to 70 years, which is far longer than most asphalt shingle roofs. The downside is that metal roofs are usually more expensive, but they typically have a lower total cost when taking lifespan and increased property value into account.
The Bottom Line: Numerous Factors are Important for Optimum Solar Energy System Design
Although solar panel tilt angle is an important consideration when designing a solar PV system, it is not the only critical factor. We consider numerous factors when designing the ideal position for your solar panels. Typically, when installing solar panels, they are flush against the roof with a small air gap to help promote solar system performance.
Want to learn more about going solar? Contact Smart Solar Energy today for a free solar audit!