Optimizing Solar Panel Performance

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Don’t fret if your roof doesn’t face south! While your solar panels may produce slightly less energy, they’ll still generate power effectively.

Optimal Solar Panel Direction for Various Goals

Below is a concise overview of the ideal solar panel direction for different purposes. Further details are elaborated upon in subsequent sections.

South

• Maximize solar power output
• Take full advantage of net metering for bill savings
• Use a solar battery and reduce grid reliance

South or Southwest

• Minimize the impact of high Time-of-Use (TOU) Rates

The optimal direction for solar panels overall is southward. In most cases, this orientation yields the highest utility bill savings and quickest payback period compared to other directions.

Key advantages of south-facing panels include:

Maximized benefits from net metering.

Enhanced solar energy generation.

Improved utilization of solar batteries.

Each of these benefits is elaborated upon below.

• For optimal solar panel output in the U.S., a south-facing orientation is ideal. The sun’s path ensures consistent exposure from the southern half of the sky year-round, maximizing sunlight absorption.

• For homes utilizing net metering, a south-facing orientation is optimal. South-facing panels produce ample power, particularly during midday when energy consumption tends to be lowest. Surplus solar energy can be exported to the grid under net metering, yielding generous compensation from the utility.

• Opt for south-facing panels if you intend to integrate a battery storage system. Their increased power output ensures sufficient energy to charge your solar batteries, even after fulfilling daytime energy requirements. This stored power serves as valuable backup during nighttime or grid outages.

Opting for a solar panel orientation ranging from south to southwest is optimal when your utility employs Time of Use (TOU) billing.

Under TOU billing, electricity rates spike during peak hours, typically after 4 PM. Generating solar power during these costly periods becomes advantageous. Facing panels southwest enhances afternoon and evening solar production by capturing more sunlight from the setting sun.

However, southwest-facing panels yield less overall solar power throughout the day. For TOU rates, the ideal orientation depends on the ratio of peak to off-peak rates:

• If peak rates are double (2x) off-peak rates, a near-south orientation is ideal.
• With exceptionally high peak rates, such as triple (3x) or more compared to off-peak rates, southwest-facing panels are preferable.

A solar installer can determine the best solar panel orientation for your roof considering TOU billing rates in your area.

However, structural constraints may limit your desired orientation. Is solar still a viable option for you? Our solar calculator provides an estimate of costs and savings based on your roof direction and utility’s TOU rates, helping you decide.

What is the Impact of Solar Panel Orientation on Output?

In the U.S., aligning solar panels due south (azimuth of 180 degrees at solar noon) maximizes output. Deviating from this direction results in reduced solar panel output.

Facing solar panels away from true south leads to decreased solar power production. The extent of this decline hinges on the direction in which the panels are oriented.

*Approximate estimates compared to south-facing solar panels; figures are for reference purposes only.

Panels facing southwest or southeast 

Solar panels positioned on roofs facing southwest or southeast typically yield around 8% less power compared to those on a south-facing roof in the same climate.

Panels facing east and west

On a standard pitch roof, panels oriented east or west produce roughly 15% less output than those facing south at the same pitch.

Panels facing north

Solar panels installed on a standard pitch roof facing north, away from the sun, generate approximately 30% less power than south-facing panels.

The precise decline in energy production is influenced by three factors:

1. Distance from south: Greater deviation from true south leads to larger energy production losses. Southwest turns result in a minor drop, westward turns see a moderate decrease, while northward turns incur the most significant loss.
2. Latitude: Energy production falls more as you move farther north from the equator. States with lower latitudes like Arizona and Hawaii, where the sun is higher, require lower tilt angles for optimal sunlight capture. Conversely, higher latitudes like Minnesota and Oregon demand steeper tilt angles for maximum sunlight absorption.
3. Roof pitch: Solar panel output over a year shows minimal difference between shallow and steep roofs. Shallow roofs capture more sunlight in summer, while steep roofs excel in winter. Though solar panel trackers can maintain optimal angles, the costs and complexities are often prohibitive.

However, steeper roofs experience more significant output drops when panels face away from the south.

What if Your Roof Faces a Different Direction?

While south-facing roofs are ideal for solar energy systems, many homeowners lack this orientation. Yet, this doesn’t negate the viability of solar installations.

Options for homeowners with non-south-facing roofs:

1. Install additional panels:

Compensate for reduced sunlight by adding more solar panels. The incremental cost of extra panels is minimal compared to the overall system expense.

2. Ground-mounted arrays:

Opt for ground-mounted solar systems, allowing optimal positioning for maximum sunlight absorption. Although they require more space and are costlier than rooftop installations, they offer easier maintenance.

3. Solar panel trackers:

Invest in solar tracking systems to enhance output by ensuring continuous sun exposure. Axis trackers, while efficient, come at a higher price compared to fixed systems, nearly doubling the cost.

While these alternatives mitigate orientation challenges, each option carries its own set of considerations regarding cost, space, and efficiency.

Does the angle of solar panels matter?

While panel orientation is crucial for optimal output, the angle of inclination also plays a role.

To maximize power generation, panel angles should be adjusted according to latitude and seasonal changes. However, fixed roof angles limit adjustability.

Solar systems are installed at various tilt angles to accommodate diverse roof pitches, ensuring cost-effectiveness for homeowners.

In summary, while the ideal panel angle can boost production, variations in angle don’t necessarily negate the benefits of solar energy.