Net-Zero Mid-Century Modern

This eight-year-long retrofit benefitted from a “house-as-a-system” approach.

When architect Carri Beer and Passive House consultant Michael Hindle began the restoration of what they now refer to as the “CarMic 1954 Net Zero Retrofit,” they knew it was going to be a challenge.  

Taking a beaten-up, enormous, outdated, 50-plus-year-old single-family home and transforming it into a modern, stylish, healthy, and energy-efficient dwelling—without losing any of the charm —would be a multi-year task. The house needed so much work, the project took eight years to complete. 

In that time, the term “money pit” would come to mind. So would the word “crazy.” But there is enough common sense to make the project Green Builder’s Green Home of the Year in the Net Zero Plus Energy category. 

Cringe-Worthy Back Story

The Catonsville, Md. home’s original footprint clocked in at what in 1954 was a pretty-good-sized middle-class dwelling: single story, 1,524 square feet, three bedrooms, two bathrooms, and a two-car garage. 

But over the years, various owners made numerous haphazard modifications, such as an ill-advised covered porch, a three-season room over the garage, a poorly refinished basement, and two extra bedrooms. These tripled the home’s size (now 4,519 square feet) and its waste potential. 

Beer is principal architect at CommONEcology, which provides net-zero and passive-house services. She once referred to the house, in a blog from Green Building Advisor, as “a never-ending nightmare of things falling and breaking.” 

There was a natural gas leak, gutters falling off, copper piping with pinhole leaks, two macerating ejector pumps leaking sewer gas, and numerous overloaded circuits. There was a dual furnace with a single-zone duct system rated for a total of 160,000 Btu/h and a 5-ton A/C, along with another 50,000 Btu/h and 2.5 tons of A/C in the three-season room, which were incapable of adequately cooling or heating the house. 

The litany of troubles continues: The yard was overgrown; the pool had a leaking, chemical-guzzling pump; 1990s fixtures proliferated; and some time-warped, now-concave windows melted the home’s vinyl siding.

Air leakage was ridiculous: According to Beer, an audit revealed that the house leaked about 1.3 times more than it should; proper air sealing would only reduce the air infiltration to about 4,200 cfm. She notes that they have designed and delivered houses of nearly this size that tested out at only about 5 percent of that total. 

So, why undertake such a massive, futile-sounding rework?

“As practitioners in the industry, we were inspired to retrofit this home to show what is possible to anyone that owns a home,” Beer says. “Knowing that deep energy retrofitting our existing building stock is critical to the health of our planet, we wanted to provide a story and a guide—provide others the inspiration and instruction, to retrofit their homes to be healthy, low energy and resilient.”

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Trades to the Rescue?

Naturally, Beer and Hindle—co-owner and principal of Passive to POSITIVE, a high-performance energy design consulting firm using the foundation of Passive House design—interviewed licensed contractors and repair personnel to do the bulk of the work, but most people they spoke to were unenthusiastic. 

Plus, there were budgetary constraints. 

The basement was a good example. A previous owner had remodeled the space into a two-bedroom, one-bath living area. But due to poor planning and choice of materials, the area turned into a moldy, stale-aired, bug and snake-infested mess.

“Asking [contractors] for a safe, moisture-proof, insulated, and air-sealed basement wall was beyond anyone’s capabilities,” Beer says. “This lack of knowledge and interest filtered all the way to installing a heat pump water heater, ‘deconstructing’ rather than demolishing, using alternatives to foam, and properly installing airtight, triple-pane windows.”

So, Beer and Hindle made many repairs and upgrades themselves, which meant lots of late nights and weekends of working. This challenge also led to creativity and ingenuity in the reuse and salvage of materials, sourcing used and vintage products, and taking the time to make conscious decisions, Beer notes.

Renovation Life Lesson

CarMic 1954 was also a great experience for their three kids (at that time, ages 4, 11, and 14), who were recruited into the project. 

“They helped lay cork floors, tape membranes, and install windows while learning why having a zero-energy, healthy house was important to the planet and to humans,” Beer says. “They lived firsthand the experience of moving in and breathing toxic, mildewed air, not being comfortable, and not feeling integrated with their natural surroundings toward contributing to the transition to comfort, safety, health and beauty in their home.” 

All three children would later give presentations about the home. They can answer most questions people might have. They have a definite desire to “educate everyone on how basic it can be to help save the planet and live in a net zero home,” Beer says.

To Beer, education is the most important thing that can come out of a homebuilding project. “It’s a huge part of the process—the education of contractors, other homeowners, and friends and neighbors around the importance of conscious change and thinking beyond the normalized corporate responses,” Beer says. “Once people get a glimpse into this life, people crave the knowledge of change and ultimately want to know what they can do to make a difference.”

Beer and Hindle have since created a Homeowner’s Field Guide to a Regenerative Deep Energy Retrofit, at to provide more insight into green construction.

Most Mid-Century Modern homes offer walls of natural lighting and minimalist detailing that allow homeowners to adopt any living and decor style with success.

Older windows were replaced with higher-performing, triple-glazed versions; the others were repurposed for other projects.

Dirt displaced from remodeling efforts was used to create a berm with native perennial flowers and other wildlife-attracting vegetation.

Carbon-negative cork is used as cladding and for flooring, acting as insulation and offering a unique appearance.