Solar Azimuth & Pitch Efficiency

Not every roof faces South. See exactly how much power you'll lose.

Roof Direction (Azimuth) For Northern Hemisphere.

Roof Pitch (Angle)

System Size (kW) Size of your solar array in Kilowatts.

Efficiency Report

Efficiency Factor

100%

Of potential output

Estimated Loss

Production lost due to angle

Impact: For a 10kW system, this direction acts like a 10kW system facing perfectly South.

How This Tool Works

The Solar Azimuth & Pitch efficiency calculator is designed to model the geometric energy loss associated with suboptimal panel placement. In a perfect world, every solar array would face True South at an angle matching the local latitude. In the real world, most homeowners have to work with the roof they have.

This tool uses trigonometry and average solar constant data to estimate your Efficiency Factor. It compares your specific azimuth (direction) and pitch (tilt) against a standard 100% efficient baseline, helping you determine if a solar investment still makes financial sense for your home.

How to Use the Calculator

Roof Direction (Azimuth): Select the direction your roof faces. 180° is South, 90° is East, 270° is West.
Roof Pitch (Angle): Select the steepness of your roof. 30° is a standard residential pitch. Flat roofs are 0°.
System Size (kW): Enter the size of your proposed solar array. The average US residential system is 6kW to 10kW.

Example Efficiency Analysis

If you install a 10kW system on a West-facing roof (270°) with a 30° pitch:

Efficiency Factor: ~82%
Geometric Loss: 18%
Effective Size: 8.2kW
Verdict: While you lose 1.8kW of capacity, a West-facing system is often highly profitable because it produces power during "Peak Demand" evening hours when utility rates are highest.

Why This Tool Is Accurate

We use a cosine-law based reduction model that accounts for the primary vectors of solar irradiation:

Azimuth Discounting: We apply a gradient weight to the North/South axis. Panels facing North are penalized heavily because they receive almost zero direct "beam" radiation.
Pitch Normalization: The tool accounts for "cosine losses" where sunlight hits the panel at an oblique angle, effectively spreading the energy across a larger surface area and reducing intensity.
The 'Effective Size' Metric: By converting efficiency into a kW number, we provide a concrete way to talk to installers about your real-world expectations.

Frequently Asked Questions

Which roof direction is best for solar panels?

True South (180°) is the optimal direction for solar panels in the Northern Hemisphere as it receives the most consistent sunlight throughout the day. However, West-facing panels are often valuable because they produce peak power in the late afternoon when electricity rates are highest.

How much energy do I lose if my roof isn't South-facing?

Typically, an East or West facing roof produces about 80-85% of the energy that a perfectly South-facing roof would. North-facing roofs are the least efficient, often losing 40-50% of potential production.

What is the best pitch for solar panels?

The optimal pitch (angle) is usually equal to your geographical latitude. For most of the US and Europe, a 30° to 35° angle strikes the best balance between summer and winter sun.

Limitations & Disclaimer: This tool calculates geometric efficiency only. It does not account for shading from trees/buildings, local weather patterns, or panel degradation over time. Consult a local solar engineer for a site-specific "PVWatts" simulation.