John Semmelhack is the owner of Think Little, a building science consulting firm based in Charlottesville, Virginia, specializing in building enclosure and mechanical system design for single-family and multifamily passive house and net-zero energy homes in the mid-Atlantic.

Since 2007, Think Little has provided consulting, testing and inspection services for more than 2,500 multifamily and single-family housing units, including several firsts – the first certified passive house residence in Virginia as well as some of the first EarthCraft certified net-zero homes.

John is a certified Home Energy Rating System (HERS) rater and an EarthCraft Technical Advisor. John is also a CPHC® (Certified Passive House Consultant), is a member of the Phius Technical Committee, and is a Phius Trainer for the CPHC training program.