The Best Direction for Solar Panels

Row of photovoltaic solar panels
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Solar panels are gaining popularity as an environmentally friendly investment that will produce renewable energy on a large scale for many years to come. Even after you make the initial decision to switch to solar panels, there are still a few things to consider—and among the quantity, size, and power capacity, you’ll want to research the best direction for solar panels to face. Whether the system is mounted on the roof, carport, or ground, the direction your panels face is a major factor in how much energy your system produces.

Learning the direction that your roof faces will help determine the best positioning for your rooftop solar panel system, since it determines how much natural sunlight the panels will receive throughout the day. If you have a company installing your panels for you, they should be able to help give you an idea of the most optimal direction, but another option is to use Google Maps. Simply type in your address and compare your roof’s direction on the satellite imagery to the provided compass grid.

The Case for South-Facing Panels

In the Northern Hemisphere, solar panels are generally more effective when they face the south. According to Energy Sage, a clean energy project developed by the United States Department of Energy to help consumers choose solar equipment, solar panels that face east or west typically produce 20% less electricity than if they were to face the south. In terms of angles, a fixed roof-mounted system should be at an angle equal to the latitude of the location where the panels are installed, usually between 30 and 45 degrees. If your roof doesn’t face the right direction, you could adjust the angle of the panels to offset the effect of direction.

That doesn’t mean you won’t benefit from solar panels if your roof doesn’t face directly south, however. Rooftop solar panels will still produce enough electricity to save you money on your utility bills even if they’re positioned in other directions. In fact, solar panels will even produce electricity if you live in a region that experiences snowy or cloudy weather conditions. In these cases, you may need to invest in a few more panels, especially if you plan to power your entire property using solar.

What to Do With a North-Facing Roof

North-facing systems are generally considered to be the worst possible location for solar production. It isn’t impossible, but will likely require additional mounting to orient the panels so that they oppose your roof’s natural slant and don’t sit flush with the roof. Consider a ground-based system or even one on top of a separate carport if a north-facing roof is your only option.

The Case for West-Facing Panels

There are several studies making a case for west-facing panels, including a survey conducted by Opower, a software company that works with electric companies to manage relationships with customers. The company examined 110,000 California homes and found that while most solar panel systems point south because it captures the most power over the course of the day, west-facing systems maximize production during the late afternoon when homeowners are more likely to run the dishwasher, turn on the lights, and watch television. In this case, the most optimum direction to face your solar panels may be somewhere between south and west, depending on what time of day you use the most energy. This way, you can take advantage of the benefits that both directions bring to the table.

Another study published in the journal Solar Energy investigated optimal solar placement using a model of a generic solar panel and calculated outputs for every possible placement in 1,000 different locations throughout the United States. In Austin, Texas, for example, west-facing arrays produced 14% less energy than south-facing ones over the course of a year; however, during the summer months, the difference was just 1%. The study also found that if they considered energy produced during peak usage hours from 3 p.m. to 7 p.m., then the western orientation was the most efficient.

What does this mean? Well, some utility companies attempt to avoid electricity usage surges in the late afternoons and evenings, so they charge extra during these periods. If you live in an area that charges more expensive utility rates depending on the time of use, it might be worthwhile to consider west-facing panels instead of south-facing ones.

Frequently Asked Questions
  • What is the best angle for solar panels?

    Deciding which angle to install solar panels is tricky because each season has a different optimal angle. In spring, that angle is 45 degrees. In the winter, it's 60 degrees. And in the summer, it's 20 degrees. In general, fixed solar panels should tilt 30 to 45 degrees.

  • Can you put solar panels on a flat roof?

    You can install solar panels on a flat roof, but they're more efficient at a 45-degree angle facing south, which you can achieve with mounts.

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