The original plan was to demolish the 1955-vintage three-bedroom house and then construct in its place a home that performs to the Passivhaus standard. According to the builder, Equitable Green Group (EEG), the old house was in relatively poor condition. But one feature of the old building saved it from complete demolition: a portion of the exterior siding contained asbestos, whose safe removal, EGG determined, would cost more than leaving the affected walls in place and rebuilding from there.

So the remodel, on a lot in Austin, Texas, features a design that involves replacing most of the existing building – which included a side wall that was knocked out in the 1970s so that the structure could be merged with an adjacent carport – and about half the foundation.

EGG’s founder, Nicholas Koch, had served as project manager for LEED consultant R&R Energy Resources, in Portland, Oregon, before moving to Austin to launch a company that, as he says on the EGG website, “would merge the innovation of the green movement with the equity movement so that advances in green building could benefit more communities.” The company specializes in geothermal heating and cooling and green building. The remodel, he adds, aims to be among the first homes in Texas to meet the Passivhaus standard.

More details from the builder

Koch told GBA that the house will measure about 1,800 sq. ft. It will be insulated with cellulose (shelves are built into the wall cavities, Koch noted, to help prevent settling) to about R-30 for the floor and ceiling and R-60 for the walls. The windows, from Inline Fiberglass, will be shaded by a 6-ft. porch roof on the front (west side) of the house. Large trees on the property shade most of the other windows during about 90% of the day and, overall, shade the building too much to make installing roof-mounted solar power practical.

The house will be equipped with an UltimateAir RecoupAerator energy-recovery ventilator (ERV), an “oversized” 1.5-ton mini-split system, and a hybrid heat-pump for both interior heat and water heating.

Koch, who is both the property owner and contractor on this project, said he is on track so far to complete the rebuild for about $60,000, adding that “it actually would have been cheaper for me to do a new construction project. So if I was to charge a client for this, I would still be profitable if I charged $80 to $100/sq. ft., which should be quite affordable for most people for a new construction project.”