Affordable, Airtight, and First of Their Kind: Dover’s Breakthrough Passive House Homes

Four homes on North Kirkwood Street in Central Dover are slated to become Delaware’s very first Phius certified buildings. The project was funded by Energize Delaware and developed by NeighborGood Partners. Designed to meet one of the most demanding residential energy-performance standards in the country, these homes achieved Phius Core Prescriptive Design Certification in 2024. In a market where high-performance construction is typically associated with higher costs, this project demonstrates that long-term energy efficiency, indoor comfort, and durability can be delivered within an affordable-housing model, remaining financially accessible to local buyers.

With design certification complete, the focus is now on construction-phase testing and documentation. The next step is ventilation-system testing and commissioning, followed by the remaining steps required for final certification. Final air-tightness is complete and has yielded some impressive results, with individual homes ranging between 0.014 and 0.023 CFM50/ft2, well below the Phius Core Prescriptive threshold of 0.04 CFM50/ft2.

Beyond meeting technical benchmarks, the project is contributing to a broader shift in how affordable housing is built in Delaware. Rather than treating energy efficiency as an upgrade or add-on, these homes are being constructed from the ground up to deliver long-term durability and comfort and low operating costs as a baseline.

These homes are also serving as a hands-on learning opportunity. New Ecology staff have supported mid-construction hard-hat tours that bring community members, builders, and other project stakeholders onto the site to see high-performance assemblies and systems before they are concealed behind finishes.