The DNREC State Energy Office (SEO) supports the adoption and implementation of energy conservation codes that help make buildings across Delaware more comfortable, affordable and energy efficient.

Regularly updating building standards for new residential and commercial construction as well as working with builders, code officials and other stakeholders to facilitate implementation are essential for lowering utility costs and supporting the state’s climate and energy goals. 

Building energy codes set standards for new residential and commercial construction. The State Energy Office adopts updated versions of the International Energy Conservation Code (IECC) for residential buildings and the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) for commercial and high-rise residential buildings.

Regular Reviews and Updates

Delaware state law (16 Del. C. §7602) requires the State Energy Office to conduct a review of Delaware’s energy code every three years. The energy office reviews model code changes, engages with stakeholders and adheres to a regulatory development process to promulgate amended versions of the Regulations for State Energy Conservation Code (7 DE Admin. Code 2101). 

2026 Regulatory Update

In April, 2026, DNREC promulgated revisions to the regulations to adopt the latest versions of the IECC and ASHRAE. This revision was effective as of April 11, 2026.

Find more information about this update in the April 2026 edition of the Delaware Register of Regulations.

The revised regulation adopts the 2024 International Energy Conservation Code (IECC) for residential buildings and the 2024 IECC and American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 90.1-2022 for commercial and high-rise residential buildings. It also adopts Appendix RE: EV Charging Infrastructure, and Appendix CB: Solar-Ready Zone, with amendments to align with corresponding statutory requirements.

State law gives counties and municipalities 12 months from the date of promulgation to implement and enforce the codes set forth in the regulation.

While implementation and enforcement are done at the local level, the DNREC State Energy Office is in the process of preparing training for builders and code officials to familiarize them with the changes in the code.

Technical Assistance and Training

The State Energy Office provides technical assistance and training materials to facilitate implementation and compliance. Technical support is available via email, at EnergyCodesDE@psdconsulting.com, and by telephone at 1-877-494-1333. The hotline is open for questions regarding the most recently adopted residential or commercial codes. Training is developed to assist builders and code officials with transitioning to Delaware’s updated code. 

Regularly updating Delaware’s energy conservation codes reduces energy use, supports utility savings, lowers greenhouse gas emissions and promotes safe, comfortable and resilient buildings. 

Related Topics:  building, climate, efficiency, energy, plumbing