Overview

In most cases, the best solar panel direction is facing south¹. Arrays that are appropriately oriented can improve energy output by up to 30% or more². However, factors such as roof slope and proximity to the equator may have some homeowners considering other directions (including north). 

So how do you know which direction your solar panels should face? In this article, we break down the best direction for any goal and the aspects that influence that decision. We even offer solutions if south facing solar panels aren’t an option. Read on to learn more.

Why does solar panel placement matter?

Before learning how to position an array, you may wonder why the position has any effect at all. So long as you point your solar panels toward the sun, they’ll produce energy, right? 

That’s partially true, but with an understanding of how the equipment works, you can generate even more energy. For maximum efficiency, solar panels need to face directly at the sun.

Within every panel exists several photovoltaic (PV) cells (units that absorb sunlight)⁷. They’re made of a semiconductor material that takes in specific wavelengths of light, called a bandgap. In fact, studies show that modern silicon cells can only take in 33% of the energy that hits them³.

Because this bandgap is so picky about what waves it absorbs, the PV cells need the sunlight to come right at them. With even the slightest turn away from the sun, these cells start to reflect wavelengths away instead of absorbing them in. 

When your solar panels only have access to a small amount of energy, it’s worth your investment to point them in the right direction. This simple adjustment, along with the ideal angle, can increase your solar array’s efficiency by a considerable amount. 

Best direction for solar panels

If you live in North America, the best direction for solar panels is facing south¹. Situated north of the equator (which puts the sun on the south side of houses), homeowners have the best opportunity to cover their power usage, top off batteries, and maximize offsets from net metering.

However, others may find reasons to face their array in different directions. Let’s learn about the best solar panel orientation for any goal.

South facing solar panels

Our understanding of why south is the best direction for solar panels in the United States starts with the equator. 

This is the imaginary line that separates the earth into two hemispheres: northern (where the US is located) and southern. It’s also the center of the range where the sun sits in the sky. So during the equinox, you’ll find it directly overhead at noon on the equator line.

What does that mean for the U.S.? Everything north of the equator line will find the sun facing slightly south.

To take advantage of this knowledge, you can point your solar panels southward. This gives them the best opportunity to absorb energy, powering your home and charging your batteries.

However, this isn’t where the benefits end for south facing solar arrays. If you live in a state that offers net metering, you can connect your system to the power grid and earn credits toward your monthly electricity bill.

West facing solar panels

As PV arrays begin orienting away from the south, they immediately become less efficient. In fact, west facing solar panels produce an average of 15% less electricity².

However, those that pay for electricity via Time-of-Use (TOU) pricing plans can benefit from the change in direction. 

TOU plans charge customers for power on a scale based on peak usage. They’re typically highest in the evening, when homeowners return from work. With panels facing southwest or true west, your array creates more energy when electricity is at its highest rates.

States that utilize a TOU pricing plan include⁸:

• California

• Arizona

• Maryland

• Delaware

• Oklahoma

• Texas

• Ohio

• Arkansas

• Louisiana

• New York

East facing solar panels

Much like west facing panels, arrays oriented to the east create about 15% less energy than average. Therefore, you should only consider this as an option if you don’t have a southside roof available².

North facing solar panels

The complete opposite of south facing panels, arrays oriented to the north provide nearly 30% less power², making them the least ideal. If you live in the continental U.S., you’ll opt for this direction if it’s your only option.

However, if you live in Hawaii or Puerto Rico, it’s a slightly different story.

The sun doesn’t stay on the equator line throughout the year; depending on the season, it moves up and down the latitudes (more on this below). During the summer solstice in June, it’s as much as 23.4 degrees north from where it started during the equinox.

This is important knowledge for Hawaiians and Puerto Ricans, who live at 19.9 and 18.2 degrees north, respectively. 

During the summer, when the sun spends more time overhead than any other time of the year, it’s actually on the north side of homes. This means if you live in Honolulu or San Juan, it may be viable to have north facing solar panels.

Directional factors for solar panel output

Distance from south

For the average American homeowner, you’ll receive the most out of an array by pointing your solar panels south. Any direction away from south outputs decreasingly less energy. Generally, you can expect efficiencies to drop by 15% for every 90 degrees²:

• Southwest or southeast: 8% less efficient

• West or east: 15% less efficient

• North: 30% less efficient

To present these guidelines, we examined a range of efficiencies from this Folsom Labs report and established a general measurement. For deeper insights into the effects of direction on solar panel efficiency, check out their article.

Roof pitch

Finally, you can expect the slope of your roof to have an effect on solar panel efficiency. A common pitch in the United States is 4/12.  But what if your house features a different build?

In Miami, Florida, it’s more common to find houses with 3/12 roof pitches. Solar panels on these slopes have better angles toward the sun, resulting in more energy production.

However, homes in Minneapolis, Minnesota, which could feature as much as 10/12 slopes to shed snowfall, are even more impacted. North facing arrays on these roofs are nearly half as efficient², making them impractical.

Alternatives if you can’t install south facing panels

While solar panel direction can have a dramatic influence on energy output, it’s not so drastic if you can’t have them facing south. With solar equipment costs at an all-time low, you may still save thousands on electricity by making the switch. Consider these alternatives if the best direction isn’t an option.

Install in a different orientation

Your array’s orientation has a major effect on efficiency, and any direction away from south can require more panels to meet your needs. This can cost a bit more in installation costs, but may still be worth the investment.

For example, let’s assume you need the standard 6.6kW system to power your home, but it needs to face east. To make up for the 15% less efficiency due to the angle of the panels, you should opt for a system that can produce 7.8kW.

While a larger system may be slightly more expensive, your electricity bill offsets could cover that in a couple of years. And with solar panels lasting up to 25 years, you’ll still see net returns over their lifetime.

Common questions about solar panel orientation

What is the best direction for solar panels?

If you live in the United States, it’s best to have your solar panels facing south. This is due to the country’s location in the northern hemisphere, which sees the sun slightly southward year round.

Is east or west better for solar panel installation?

Most homeowners can expect the same drop in output regardless of eastern or western orientation. However, if you live in a state with Time-of-Use electricity pricing, west facing solar panels can save money during peak hours.

Do seasons affect solar panel direction?

In the continental United States, seasons won’t affect the direction of solar panels. However, those living in Hawaii or Puerto Rico may consider a different orientation due to their location closer to the equator.

Is solar panel angle or direction more important for efficiency?

While solar panel tilt angle plays a role in overall output, it’s more important to face your array in the right direction. 

Want to learn more about how solar panels work?

Embarking on the solar journey can be both exciting and daunting, especially when it comes to determining the optimal placement for your solar panels. Rest assured, we're here to simplify the process for you.

Our expert Solar Advisors guide you through the complexities and details of solar—from understanding your energy bills, to installation and more. And each Sunrun solar system is custom designed to fit your home’s unique needs.

As the nation's #1 home solar & battery installer, we provide dedicated support from initial system design to powering on your system. Our personalized approach ensures that you make the right decisions about panel placement, enabling you to harness the full potential of solar energy without the stress.

Sources

1. Solar panel orientation - Energy Education.

2. How much less efficient are north-facing solar modules?

3. The Shockley-Queisser limit 

4. Community Solar | SEIA

5. Should your PV systems face west with California’s Net Billing Tariff (NEM 3.0) rules? | Aurora Solar.

6. How Does Solar Work? | Department of Energy.

7. US Latitude and Longitude Map with Cities

8. Time-of-Use Energy Plans By No Means Unique to Our Region | SDGE | San Diego Gas & Electric