Program Solar-Ready Zones
Category Regulatory Policy
Implementing sector State
Last Update
State Delaware
Start Date
Technologies Solar Water Heat, Solar Space Heat, Solar Photovoltaics

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.


  • 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.


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.

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