Before & After: An Architect Builds Net Zero Row House in Washington, DC


Architect Will Teass of Teass/Warren Architects has just completed renovating this sensational Net Zero Row House for him and his family in the Capitol Hill neighborhood of Washington, DC. The NetZeroRowHouse began as two architects renovating their 1925 home for their family of four. The simple notion of adding solar panels started the journey to create a Net Zero Row House.

From the architect: “As an architect, we consider ourselves as agents of change and we need to personally practice what we professionally preach. Climate change, like a site or a client’s wish list, now shapes the design process. It is critical that we consider the energy and carbon footprints of the building we design, as they will be here longer than we will. When we build a house for a client, or ourselves, there’s simply no excuse not to implement these principles. If we don’t, who will?”

Continue below to see the rest of this home tour along with tips and tricks from architect Will Teass of Teass/Warren Architects on how to build an eco-conscious home — along with images prior to the renovation!


NetZero design principles are applicable to all types and sizes of buildings, including urban row houses. The first step is to design a solar array to maximize the production of on-site energy, ideally producing enough electricity over the course of a year to offset the amount of electricity that the home consumes. All appliances, including heating, cooking, and hot water generation are specified as all-electric to decarbonize the home and sever the fossil fuel umbilical.


Using smart electrical panels, consumption is tracked on a circuit by circuit-based approach providing highly detailed data that illustrates how much each plug, light, and appliance is using. Alerts are provided if a circuit or device is using more than expected electricity. In the case of #NetZeroRowHouse, the exterior envelope (walls and roof) is highly insulated and sealed to minimize air infiltration, improving the thermal quality. New windows maximize insulative value and utilize low-e coatings to reflect solar energy in the summer.


Indoor air quality is also critical when new construction / major renovations are considered. Energy recovery ventilators provide fresh air that uses either outgoing warm or cool interior air to treat or condition incoming outside air. Heat pump technology, used for both hot water and heating/cooling, provides additional efficiency (and reduced energy bills).


Replacing the gas range with an electric induction cooktop provides a superior cooking surface. Smart appliances link to your smartphone, reminding you when the oven is left on or the refrigerator door is ajar. Combating climate change can start in your own home using Net Zero design principles. All of the systems are invisible; the house looks and lives like any other.


Details about Will Teass’ home:

The original 1925 brick rowhouse was completely reconstructed and expanded. The front façade and porch were retained to preserve the character of the street. A third-floor addition, for the principal suite and home office, is setback from the existing roof line, creating a private roof deck. The lower cellar level was fully excavated with a new entrance to access the accessory dwelling unit / rental apartment. The addition is clad with a combination of standing seam metal, nickel gap cementitious siding, and thermally modified cypress. Large glass doors, with high-performance glazing, bring in abundant natural light while minimizing solar heat gain.


The rear wall was removed, and the addition pushed back to expand living space on all four levels. The ground level plan maintained the proportions of the living room, but the stair to the second floor was flipped creating a large coat closet and better access to the roof deck. Passing through a cased opening threshold, separating the powder room and wet bar, the kitchen and dining room feels larger by adding a single step down to achieve nine-foot ceilings. A large glass bifold door opens to a rear deck with a shade structure and a rear garden which doubles as a parking area.


Two bedrooms and two bathrooms and a kids’ den are located on the second floor. A custom stair from the second floor to the third is made up of solid white oak boards that both support each floating stair tread, as well as form the third-floor guardrail. A skylight above allows for the interior of the space to be naturally lit. A home office with a wet bar is adjacent to the roof deck, providing excellent access to the north-facing / shaded deck for morning coffee or evening cocktails.


Large windows and a full areaway under the porch provide excellent natural light for the cellar apartment. A galley kitchen provides the full complement of counter space and appliances. A den, with barn doors creates an ideal remote workspace. The bedroom suite features a dressing room that can be closed off from the rest of the unit for privacy.


The goal of a NetZero house is to produce as much energy as it uses. A 7.92 Kw array on the roof, with 23 panels produces about 1.1 MWh during peak summer months, pushing excess power back into the electrical grid. The existing gas line was abandoned, and heating (both space and hot water) and cooking are from all-electric sources. Highly efficient ducted mini-split air handler units are located on each level, providing ideal thermal comfort in the vertical home.


Two quiet heat pumps (one for each unit) are in the rear yard, with SEER rating exceeding 17. The exterior envelope is reasonably tight by modern standards and energy recovery ventilators provide fresh air that is conditioned with an enthalpy wheel, tempering heat, and humidity. Smart electrical panels provide detailed usage on a circuit-by-circuit basis for both units, including the amount of electricity from the solar panels. A single heat-pump water heater provides ample hot water using the same technology as the refrigerator.


What We Love: Through his commitment to design for sustainability, the architect has shown that it is possible for existing homes to be updated in a way that is both attractive and energy efficient. Large windows maximize natural light throughout the interior living spaces while a fabulous roof deck provides the occupants with a family hangout space to enjoy outdoor living whilst living in an urban environment. Overall, we are loving how the architect took an older home and gave it a greener future.

Tell Us: What are your thoughts on the renovation of this net zero row house? Are there any details you would change? Let us know in the Comments, we love reading your feedback!

Note: Check out a couple of other incredible home tours that we have spotlighted here on One Kindesign in the U.S. capital of Washington, DC: Mediterranean Revival home boasts drool-worthy interiors in Washington DC and Light-filled contemporary home renovation in Washington, DC.










One Kindesign has received this project from our submissions page. If you have a project you would like to submit, please visit our submit your work page for consideration!

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