When most homeowners think about solar panels, they assume south-facing roofs are essential for maximum energy production. This conventional wisdom has prevented many families from considering solar simply because their roof doesn't face "the right direction." But what if the conventional wisdom is outdated?
Solar panels that face east or west will produce about 15% less energy than those installed on a south-facing roof. However, this single number doesn't tell the complete story. The best orientation for your EcoBoss solar system depends on several factors beyond just total annual energy production.
The Total Energy Production Comparison
Let's start with the fundamental question: how much less power do east-west systems actually produce compared to south-facing arrays?
Annual Energy Output Data
Panels on roofs that face 20% east will generate 85% of those on a roof that's oriented south, while roofs tilted 20% to the west from true south will still generate 89% of what a southern-facing roof will.
Installing solar panels orientated directly east or west will typically only have a drop off in generation of about 25% compared to that of a south facing array.
An ideal east-west setup only loses 10 or 15% of its annual production vs. a perfect south-facing system, while on a typical rooftop with non-ideal angles, it's more like a 20% drop in electricity production.
Real-world example: An east-west split in London generated 18.59kWh while south-facing panels in Oxford generated 24.28kWh on a comparable April day—the east-west system produced 75% of the south-facing output.
The Key Insight: Capacity vs. Orientation
Here's what changes the equation entirely: east-west roofs often allow you to install significantly more total panel capacity than single-orientation roofs.
The yield per module might be a little less in East-West facing systems, but the total number of installed modules outweighs this, leading to much better total yields per m² roof surface—this difference can be as much as 25%.
Despite the penalty for not facing south, installing panels on both east and west roofs could produce 60% more power than if you had a north-south facing roof, because you can fit significantly more total panels.
Bottom line: A 10kW east-west system producing 85% efficiency generates 8.5kW—significantly more than a 6kW south-facing system producing 100% efficiency (6kW).
Daily Generation Profiles: The Critical Difference
While south-facing arrays may produce more total energy, east-west systems generate power when it's more useful—and potentially more valuable.
South-Facing Generation Profile
The typical daily generation profile of a south facing PV array follows a uniform bell shaped curve with a large peak in the middle of the day, reaching peak generation at approximately midday.
Typical south-facing hourly pattern:
- 7:00 AM: 5-10% of peak output
- 9:00 AM: 40-50% of peak output
- 12:00 PM: 100% peak output
- 3:00 PM: 50-60% of peak output
- 5:00 PM: 15-20% of peak output
- 7:00 PM: Minimal output
East-West Generation Profile
The daily generation profile still follows a bell-shaped curve, similar to that of the south facing system, except that it adopts a flatter and wider shape, giving the advantage of having a wider power production window.
East and west panels both generated about the same amount of power—9kWh each—with the combined east-west system demonstrating how both orientations contribute throughout the day.
Typical east-west hourly pattern:
- 7:00 AM: 15-25% of peak output (east contributing)
- 9:00 AM: 50-60% of peak output
- 12:00 PM: 75-85% combined peak output
- 3:00 PM: 60-70% of peak output
- 5:00 PM: 35-45% of peak output (west contributing)
- 7:00 PM: 10-15% output (west still producing)
Both East and West generated about the same amount of power, and the average UK household uses ~10kWh per day, meaning you could completely offset energy use with half the panels on an east-west split.
When East-West Orientation Makes Financial Sense
Beyond just kilowatt-hours produced, several factors make east-west systems economically attractive—sometimes even superior to south-facing installations.
Time-of-Use Electricity Rates
In states like California, Arizona, and Texas, peak electricity rates from 4-9 PM can reach 40-50 cents per kWh, while midday rates may only be 15-20 cents.
West-facing arrays generate power precisely during these premium pricing windows—a west-facing array generates power when it's most valuable, not just when there's the most sun.
Example calculation (Phoenix, AZ with time-of-use rates):
- South-facing system: 30 kWh daily at average rate of $0.25/kWh = $7.50 value
- West-facing system: 27 kWh daily, with 60% during peak hours at $0.45/kWh = $8.10 value
The west-facing system produces 10% less energy but delivers 8% more economic value.
Self-Consumption vs. Grid Export
Since east-west panels produce electricity more evenly throughout the day, they can reduce the amount of energy drawn from the grid during peak hours, which are often more expensive.
Although the total solar energy production will be lower for east-west facing solar panels, they produce more electricity during the most active times of the day for energy consumption (between 9 am - 5pm).
Household energy pattern match: The standard domestic home will typically have a load profile containing a base load and two peaks—one in the morning and a larger peak in the evening when everyone returns home after work.
East-west systems naturally align with this usage pattern, reducing reliance on expensive grid electricity during morning and evening peaks when solar generation from south-facing arrays has dropped off.
Future-Proofing Your Investment
Even if you have traditional net metering today, many utilities are moving toward reduced compensation for solar exports, time-of-use rates, and peak demand charges.
As net metering policies become less favorable, self-consumption becomes more important. East-west arrays excel at self-consumption by matching generation to typical household demand patterns.
The Grid-Scale Benefit: Duck Curve Solutions
Utilities and energy agencies are looking for creative solutions to help alleviate afternoon peak loads—one such solution is orienting solar PV panels to the west so that they produce more power in the afternoon during peak load times.
This is one of the main drivers for the incentive the California Energy Commission is offering to users who install west-facing rather than south-facing systems.
While east-west solar arrays may have a reduced total output (15% less according to Sheffield Solar), the value of the electricity they produce is inherently higher in most markets due to the smoothing of the array's generation curve, generating more electricity during morning and evening hours and less during the midday peak when electricity is at its cheapest.
Practical Advantages of East-West Systems
Beyond energy and economics, east-west installations offer several practical benefits:
Higher Panel Density on Flat Roofs
The most important advantage of east-west solar systems is the ability to install a higher density of solar panels in a limited space on flat roofs.
Better Land Utilization—more panels can be installed in the same footprint due to reduced row spacing.
Lower Installation Costs
Since the installation of this system requires fewer structures and connection cables, the east-west solar panels save 24% of the costs required for mounting piles and steel structures.
Flatter Profile means less wind load and lower material costs.
Improved Wind Resistance
The east-west arrays are installed at a lower height and inclination angle than the south-facing arrays, which reduces their exposure to wind with a small tilt angle and the aerodynamic construction of the system.
Better Summer Performance
During the summer season, when the sun is high in the sky, the total energy of east-facing PV systems is closer to the total energy of south-facing systems—thus, the closer the solar system is to the equator, where the sun rises higher in the sky throughout the year, the greater the total energy production produced by the east-west solar panels.
Real-World Performance Comparison
Let's examine actual performance data from an EcoBoss monitoring study:
Phoenix, Arizona - 5.22kW System Comparison
Using PVWatts from the National Renewable Energy Laboratory, annual generation for identical 5.22kW systems showed: south-facing systems produced the highest total output, but west-facing arrays offered compelling financial benefits due to alignment with peak rate timing.
UK Residential Installation
East panels and West panels both generated about 9kWh on a typical spring day, demonstrating balanced contribution from both orientations throughout the day.
Commercial Installation (Netherlands)
Over the 15 year life of the Dutch SDE+ subsidy, the system owner can generate nearly 20% more profit with an East-West system at a slightly higher return on investment, despite south facing systems producing nearly 7% more yield per Wp.
When to Choose South-Facing
South-facing remains optimal for specific situations:
Off-Grid Systems
If you have an off-grid solar panel system, pumping system, or any current-based system, go with the south-oriented systems because you need high current to charge the battery—as long as you have high current, you have a higher charging rate.
Maximum Annual Production Priority
For a standard 4kWp system facing south, it is expected that the system will generate approximately 4,060kWh per year.
If your goal is purely maximizing total kilowatt-hours per year—for example, with legacy net metering agreements that pay full retail rates for all exported energy—south-facing orientation produces the most total energy.
Limited Roof Space (Single Orientation)
If you only have one suitable roof section and it faces south, this remains the best choice for that specific constraint.
The Verdict: It Depends on Your Situation
The answer is it depends—it depends on how you use your electricity, and what time of day your electricity demand is highest.
Choose South-Facing If:
- You have generous net metering with 1:1 credit for exports
- Maximum annual kWh production is your priority
- You have off-grid or battery-based systems requiring high peak current
- You only have one roof section available (facing south)
- Your electricity rates don't vary by time of day
Choose East-West If:
- You face time-of-use electricity rates with expensive afternoon/evening peaks
- You want to maximize self-consumption
- You have limited roof space and can double your panel capacity with east-west installation
- Your household has high morning and evening energy demand
- You want to future-proof against changing net metering policies
- You have flat commercial roofs where row spacing allows higher panel density
Consider Hybrid Approaches If:
- You have multiple roof sections with different orientations
- You can combine south, east, and west arrays for optimal coverage
- You're adding to an existing system
Making the Right Choice for Your EcoBoss System
Since there are so many moving parts, it's best to consult with a local solar installer to figure out what's best for your unique situation—an expert can help you decide if specialty racking is a good option, figure out what angle is best based on your exact location, and even determine if solar is right for you in the first place.
Key factors to evaluate:
- Your electricity rate structure (flat rate vs. time-of-use)
- Your daily usage pattern (when do you use most power?)
- Your roof characteristics (available space, orientation options)
- Your location (latitude, typical weather patterns)
- Your goals (maximum production vs. maximum self-consumption vs. maximum economic value)
Conclusion
The question "which orientation produces more energy?" has a simple answer: south-facing arrays produce the most total annual kilowatt-hours. However, the more important question is: "which orientation provides the best economic return and meets my energy needs most effectively?"
East-west systems can produce plenty of power, and direction and angle usually don't get in the way of a productive rooftop solar installation—the bigger blockers tend to be shading, roof size, local electricity prices, and local solar power policies.
For many homeowners in 2025, especially those with time-of-use rates or limited net metering, east-west solar installations can actually deliver superior economic performance despite producing 10-20% less total energy than south-facing arrays.
Your EcoBoss solar consultant can run detailed simulations comparing different orientations for your specific location, roof configuration, and electricity rate structure to determine which approach maximizes your return on investment—because sometimes, the "wrong" direction is actually the right choice.
Abstract
South-facing solar panels produce 10-20% more annual energy than east-west configurations, but this doesn't tell the complete story. East-west systems offer extended daily generation windows (7 AM - 7 PM vs. 9 AM - 5 PM), better alignment with household energy consumption patterns, and higher economic value in regions with time-of-use electricity rates. On roofs with both east and west sections, total panel capacity can increase 50-60% compared to single-orientation installations, offsetting the per-panel efficiency reduction. For time-of-use rate customers, west-facing panels generating during expensive afternoon peak periods (4-9 PM at $0.40-0.50/kWh) can deliver higher economic returns than south-facing panels producing more energy during cheap midday periods ($0.15-0.20/kWh). The optimal orientation depends on electricity rate structure, daily usage patterns, roof configuration, and whether maximum total production or maximum self-consumption is the priority.
Keywords: solar panel orientation, east-west vs south-facing, time-of-use rates, self-consumption, bifacial solar systems
