Window Overhang Shading Calculator

Calculate shade depth for passive cooling design

Project Details
Enter your measurements and requirements
Results
Calculated estimates for your project
Required Overhang Depth19.6"
Summer Shading100% (as desired)
Winter Shading6%
Equinox Shading29%
Summer Solar Altitude73.5°
Winter Solar Altitude26.5°

Additional Information

About This Calculator

Our window overhang calculator helps design roof overhangs and awnings that shade windows in summer while allowing solar gain in winter. This passive solar design strategy can significantly reduce cooling costs without expensive mechanical systems.

The calculator uses solar geometry based on your latitude to determine sun angles throughout the year. Since the sun is high in summer and low in winter, a properly sized overhang blocks harsh summer sun while allowing warming winter sun to enter. This is especially effective for south-facing windows.

This tool is valuable for homeowners adding awnings or pergolas, builders designing energy-efficient homes, and anyone asking "how wide should my roof overhang be?" or "how do I shade my windows in summer?" Proper overhang sizing is a one-time investment that pays dividends for decades.

How to Use This Calculator

Follow these steps to calculate your ideal overhang depth:

  1. Enter your latitude (find from maps or GPS - US ranges from 25° to 49°)
  2. Enter your window height in inches
  3. Enter the height of the overhang above the window top
  4. Set your desired summer shading percentage (100% for full shade)
  5. Review the required overhang depth and seasonal shading results
Frequently Asked Questions

Free Window Overhang Calculator - Passive Cooling Design | DIYProject.ai