Phius Zero Historic Renovation


This historic home in Oak Park was in need of updating, with deferred maintenance inside and out requiring extensive work. This created an opportunity to rethink the house for a modern family in the 21st century, with an updated plan, a strong connection to the yard from the kitchen and new mudroom, covered patio, and flexible rooms for work-at-home, gym, or guest functions. The insulation and mechanical systems were upgraded to Phius levels, and a solar PV array added to meet annual net zero energy performance. With minimal upfront energy expenditure, the home’s operational carbon was reduced by 100%, and the house is a delightful place for the young family to grow into. Read more about this project here.


“We worked with TBDA for our PHIUS Source Zero historic retrofit project, and could not imagine having worked with anyone else. The depth of knowledge that Tom and his entire team possess about passive houses, plus beautiful architectural design and just being all around kind and enjoyable people, makes working with TBDA a dream. Highly recommend for anyone looking to bring a low-carbon approach to new construction or renovation!”


Owner of Phius Zero Historic Renovation, Oak Park, IL


General Contractor
Bosi Construction

Structural Engineer
Carsello Engineering

Civil Engineer
Haeger Engineering

Third-party Testing and Verification
Eco Achievers

Energy Use per Architecture 2030
With Solar: EUI = -3.13, 106% reduction; Without Solar: EUI = 8.26, 83.3% reduction