Solar-Ready Zones

This rule applies to new buildings seeking construction permits on or after January 1, 2025.

In 2023, Delaware HB 11 was enacted, adding a provision for “Solar-Ready Zones” to the commercial building code. These rules apply to new commercial buildings with a foundation footprint of 50,000 square feet or more.

Solar-Ready Zones are sections of the building’s roof or overhang reserved for future installation(s) of solar photovoltaic or solar thermal energy systems.

Solar-Ready Zones shall be located on the roof of buildings up to 5 stories above grade with low-slope roofs or slanted roofs facing 110 to 270 degrees from true north. Zones must also comply with Solar Ready Zone – Commercial rules from the International Energy Conservation Code (IECC) and comply with requirements from ASHRAE Standard 90.1.

Exemptions: 

• Buildings with existing permanent on-site renewable energy systems, 
• Buildings with Solar-Ready Zones which are shaded for 70% of annual daylight hours, 
• Locations with attestation from a solar energy design professional that the solar radiation is not suitable for a Solar-Ready Zone, 
• Cases where a design professional certifies that extensive rooftop equipment, green roof areas, skylights, or other obstacles would prevent Solar-Ready Zone placement.

Requirements:

Construction documents must indicate:

• The Solar-Ready Zone
• Conduit from the Zone to the electrical service panel or hot water system
  • The main electrical panel must have at least one 2-pole breaker for future solar installations labeled as “For Future Solar Electric”
• Structural design loads of the roof
• The total Solar-Ready Zone area must not exceed 40% of the roof area
• The Solar-Ready Zone shall be a single area or small sub-zone areas
• Each Zone shall be at least 5 feet on its shortest dimension
• Solar-Ready Zones shall be free from obstructions including pipes, vents, and HVAC equipment
• A certificate must be displayed conspicuously near the electrical panel or water heating system, indicating the solar-ready zone.