Washington, DC
Annual Average Daily Solar Radiation

Latitude: 38.83 N Degrees
Longitude: 76.67 W Degrees
Elevation: 47 Meters
System Tilt: 30 Degrees
Annual Total BTU's per square meter (10 tubes): 3,602,086

Please read the Collector Tube Efficiency and System Sizing sections before using this chart.

This page provides solar radiation values for Thermomax Solar Collectors and expected gallons of water raised by 60 degrees F. The average daily radiation data are from University of Wisconsin EES Report No. 44 - 2 (F - Chart Data). Thermomax collector (average) efficiency of 70% is used for this chart.