How did their journey begin? In 2014, they found a 107-year old Victorian home on a small city lot in Minneapolis. Serendipitously, Stewart had stopped by a Home and Garden Show, where he heard about the concept of a “net-zero energy” home. Having been intrigued by renewable energy since the energy crisis in 1973, he told me, “When I learned about Net Zero Energy homes, a light bulb went on.” Could they remodel an existing home such that it would not contribute to climate change? The next year of design and two years of construction proved that they could. 

Unique Features of the Home

Typical to most net-zero energy homes, this old Victorian was retrofitted with all LED lights, triple pane windows, and efficient, ENERGY STAR appliances. No gas appliances are in the house, eliminating the need for combustion venting and keeping the indoor air quality healthier (the code-required carbon monoxide detectors will never be triggered). What is not typical is that this home was a remodel—so several innovative ideas needed to be incorporated. Below, we share a few highlights, excerpted and slightly modified from Stewart’s “Innovations” Flyer he wrote himself to share his knowledge.

3.    Insulating the basement without tearing up the flowerbeds.

A tight house needs to keep heat in the basement from leaking out. Typically in remodels, basement walls are insulated on the inside (which would have lost square footage and would not have been very effective), or a deep wide trench is dug to insulate the foundation (which would have made a huge mess, and there was not much room on the lot to do so). This project used the “Cocoon” method of sucking out a four-inch-wide slice of dirt all the way down to the footings of the foundation, then inserting a one-inch foam sheet and 3 inches of sprayed foam. The net insulating effect is R-30, with very little mess to clean up. (See more about excavation-less insulation retrofits.)

4.    Making a roof fit for solar panels. 

The original 1907 house had a “balloon” frame constructed of slender 2″x4″s—not suitable for solar photovoltaics (PV). The Hermans added a new roof of plywood I-beams on top of the old roof. The space between the I-beams was filled with 10 inches of foam insulation; combined with the 6 inches of fiberglass batting under the old roof, they were able to insulate the roof to R-80. The roof supports 42 solar collectors—weighing one ton in all. Supporting all this new construction is a massive laminated ridge beam, which workers installed by hand. They added another 12 solar collectors on the detached garage, resulting in a 17-kilowatt solar photovoltaic array that produces more electricity than the house consumes (hence, “Net Zero”).

Never Truly Retiring From Teaching

Back in 1978, Stewart Herman wrote Energy Futures: Industry and the New Technology. Now, he is writing articles, has created brochures, and offers free tours and speaking engagements about their home. Why? He told me, “Linda and I intended this house to be a teaching tool for anyone who wants to renovate their home.” As Stewart later wrote in an article for The Cresset, “We had a mission and a message for the wider world. As (retired) teachers, we wanted to demonstrate that an ordinary old house on an ordinary, small, urban lot could be purified of fossil fuel and accommodate all the technology needed to achieve net-zero. More ambitiously, we wanted the house to demonstrate to skeptics that a comfortable lifestyle and environmental sustainability need not clash and that carbon emissions could be lowered drastically without any sacrifice in comfort or convenience. In other words, we thought we weren’t just building for ourselves.” Stewart has loved the process and results so much that he is spreading the word to other aging baby boomers.

The Best Surprise of All

With one of the only 100-year-old homes in the country to be LEED Platinum and Net Zero Energy certified (at least that we know of!), the Hermans clearly met their goals. On an annual basis, for their excess solar production, they receive more back from in cash from the utility than they pay in utility bills. With no gas combustion in the house, their insurance rates decreased. But the best part? “I had no idea what this house would be like to live in. It’s been a real surprise: no cold spots, no drafts, no moisture on the windows condensing in the winter, no noise from outside. It is remarkably comfortable for old bones.” The idea of aging in place never sounded so good.