RV/Van Life Roof Space Calculator
Created by: Sophia Bennett
Last updated:
Plan your RV or van solar panel installation by calculating usable roof space. Account for vents, fans, AC units, and other obstructions to determine how many solar panels can fit and your maximum wattage capacity.
What is an RV/Van Life Roof Space Calculator?
A Roof Space Calculator helps RV and van owners plan solar panel installation by calculating usable roof area after accounting for vents, fans, AC units, and other obstructions. This tool determines how many panels can fit and the total wattage possible on your roof.
Whether you're building a new van conversion or upgrading your RV's solar system, this calculator helps you maximize solar capacity while maintaining proper clearances and access to roof-mounted equipment.
Understanding Roof Space Planning
Total Roof Area: Length × Width of your roof surface
Obstruction Area: Space occupied by vents, fans, AC, antennas
Usable Area: Total area minus obstructions and clearances
Panel Capacity: Usable area ÷ (panel size + mounting gaps)
Frequently Asked Questions
How much roof space do I need for solar panels?
A typical 100W panel is about 47" x 21" (6.8 sq ft). Plan for 7-8 sq ft per 100W with mounting gaps. Most vans fit 200-400W, larger RVs can accommodate 400-800W. Account for vents, fans, and AC units when measuring available space.
Should I leave space between solar panels?
Yes, leave 1-3 inches between panels for airflow, expansion, and wiring access. Panels run cooler with ventilation underneath, improving efficiency. Tight spacing can lead to heat buildup, reducing power output by 10-25% in hot conditions.
How close to the roof edge can I mount solar panels?
Leave 4-6 inches minimum clearance from edges for water drainage, wind resistance, and access. Some roof shapes require more clearance. Consider where water flows off your roof during rain and avoid blocking drainage paths.
Can I mount solar panels over my roof vent or fan?
Generally no - vents and fans need unobstructed airflow. However, you can mount panels around them, leaving 6-12 inches clearance. Some van builders create custom brackets to mount panels above fans at an angle for ventilation.
What's the best way to maximize solar on a curved van roof?
Use flexible panels that conform to curves, or mount rigid panels on raised rails that span the curve. Flexible panels lose 5-10% efficiency but maximize usable space. Rigid panels on rails provide better cooling but may reduce headroom inside.
How do I account for roof obstructions in my solar layout?
Measure each obstruction (vents, fans, AC, antennas) and add 6-12 inches clearance around each. Sketch your roof with accurate measurements. Consider future additions like a fan or AC. Planning ahead prevents costly reinstallation.
Should I use one large panel or multiple smaller panels?
Multiple smaller panels offer more layout flexibility around obstructions and easier replacement if damaged. One large panel is simpler to wire but leaves less room for other roof items. Match panel size to your largest unobstructed roof area.
How much weight can my RV roof support?
Most RV roofs support 300-500 lbs distributed load. Solar panels weigh 15-25 lbs each. A typical 400W system weighs 60-80 lbs plus mounting hardware. Consult your RV manufacturer for specific limits and mounting recommendations.
Sources and References
- AM Solar - RV Solar Installation Planning Guide
- Renogy - Solar Panel Mounting Best Practices
- Winnebago - RV Roof Weight Capacity Specifications
- Far Out Ride - Van Conversion Solar Layout Guide