zerow house: zero energy Row House

The design of the ZEROW HOUSE adopts the row-house typology, specific to the urban fabric of Houston’s Third Ward community, as a primary precedent. Our design addresses the small size and limited budget of typical row houses through replication, innovative use of current technologies, local materiality, and an understanding of life-cycle costs.

The ZEROW HOUSE will be able to produce all the energy needed for its operation on site through the use of a photovoltaic array and solar hot water system that collect solar energy.

row house re-imagined

The ZEROW HOUSE is a home designed specifically for Houston, with a site in the heart of the city at Project Row Houses to come back to after the Solar Decathlon. The row houses typical to Houston’s Third Ward, where Project Row Houses is located, are 19th century high-density urban housing derived from traditional low-income Carribean-type houses found across the South. Also called shotgun houses, where rooms lead directly into one another in a line, these affordable and small houses are lined up in rows for blocks. These row houses have a beautiful, recognized form that resonates with the historic significance and culture of the Third Ward. The design of the ZEROW HOUSE is based on respecting the character of the existing homes and community, and re-imagining the row-house typology in terms of what it means to be an affordable solar house for Houston that will be able to produce all the energy needed for its operation on site.

Rethinking organization

The ZEROW HOUSE is organized around two cores which serve as the basis for the re-thinking associated with the design of our row house: the Wet Core and the Light Core. The wet core contains all systems associated with water and energy. The light core serves as the primary source for daylighting in the house and as a flexible extension of the living space. Public and private spaces (living areas and bedroom) are created between the two cores.

Light Core

As a flexible, exterior space shaded by a cantilevered structure, the light core is a direct extension of the interior living space, blurring the boundary between interior and exterior. It serves as a psychological device that allows for a continuous projection of the indoor living space, without the need for energy to cool it, as well as a literal part of the living space when opened. Exterior living can be achieved in Houston during a large part of the year becuase the climate is often pleasant outside of the summer months.

Wet Core

The wet core packages all of the main wiring and mechanical components of the ZEROW HOUSE into one central unit. Physically, it is an 8’x10’ space in the house that bundles the kitchen, bathroom, washer and dryer, electrical, plumbing, HVAC, and solar systems. The design of one core to contain all of these functions allows for a significant reduction in cost and materials required for the installation and maintenance of systems that are both traditional and innovative. Designed with prefabrication in mind, the wet core holds promise for building cheaper houses in the future by allowing contractors to bring in the self-contained, pre-assembled unit and build the comparatively inexpensive house frame around it.

Material Selection
Due to the scope of the project and our limited budget, there was a requirement for the use of affordable, sustainable, and replicable materials. Much thought was dedicated to the design of our millwork and storage systems, utilizing IKEA, ELFA, and do-it-yourself products to create a system that is not only affordable and easily accessible to Houston residents, but that also takes environmental impact into consideration.

Durability (relating to life cycle costs) is also a large factor in the material choices. This usually correlates to an upgrade not only in the product, but also in the price, and so where available, we were able to use products that had a more expensive price upfront, but had a long life cycle and greater durability.

	Trex Decking Trex is an incredibly durable material that also has a high recycled content: 50% recycled plastic and 50% recycled wood. We were able to use this sustainable product on our deck system, where the need for durability is necessary in the hot and humid Houston climate.
	Galvalume Siding We chose to use galvalume siding on the ZEROW HOUSE based on its ability to resist corrosion and its ease of maintenance. Wood siding in Houston's humid climate has the tendency to rot quickly, which we wanted to avoid. Galvalume siding is also a reference to the small-metal-building type commonly found around Texas. Also, the metal panels are made from 25%-35% recycled materials.
	Bamboo Floors Our use of bamboo, a natural, fast growing wood, is one example of choosing durability over cost. Bamboo is traditionally more expensive than a less sustainable laminate or VCT flooring, but is also more durable than either of these options. Because the floor itself is a significant feature of the house, as it is unbroken throughout the entire house, the benefits of its natural beauty, durability, and quick growth outweighed the cost.
	Home-made Shelving + ELFA Hardware The living room houses a flexible shelving system designed with ELFA hardware and do-it-yourself shelves that can function as a workspace, entertainment area, and storage space for books, movies, magazines, etc. We wanted to demonstrate that our interior systems could be do-it-yourself, as well as potentially customizable.
	Zero-VOC Paint and Primer To create a healthy living environment, we used only low and zero-VOC paint and primer. Volatile organic compounds (VOCs) are solvents used in standard paint. When paint dries, VOCs evaporate, leaving behind their odor. This diminishes air quality and can be harmful to your health. The palette of the interiors became increasingly important to make the ZEROW HOUSE feel like a home. Neutral paint is used for the walls, and important design aspects are emphasized with accents of color, such as the subtle use of blue for the wet core.
	IKEA Cabinetry The kitchen is a unitized culinary work space that maximizes the amount of storage available along the length of the wet core. IKEA millwork runs to the ceiling, and the careful placement of kitchen appliances allows for maximum space and efficiency in a small kitchen area. As a company, IKEA is making a great effort to use materials that are environmentally friendly. They are slowly requiring all of their wood to be Forestry Stewardship Council (FSC) certified. As of 2009, they require their composite wood (used extensively in our cabinetry) to be low in urea formaldehyde.

SOLAR TECHNOLOGY: PHOTOVOLTAICS

Our team used a photovoltaic system that is available off-the-shelf so that a typical homeowner would be able to purchase them. We designed an appropriately sized array for the size of the house, producing 4.2 kW, rather than one that generates an unneccessary amount of energy. Our solar panels are angled at 15° in both Houston and in Washington, D.C, although orientation differs for each location. This strategy allows us to be exposed to the maximum amount of sunlight during the year. Our solar panels are hooked up to the power grid system, which means that when the ZEROW HOUSE produces excess energy, the electric meter turns counter clockwise as opposed to clockwise. We are essentially storing the extra power that we produced in the grid, which is a much more efficient storing system than batteries. We are giving electricity back to the power company; so technically the power company should pay the user for helping them produce power.

SOLAR TECHNOLOGY: SOLAR THERMAL COLLECTORS / SOLAR HOT WATER SYSTEM

Our solar thermal collector is a device that absorbs thermal energy from the sun and converts it into usable heat. The heat is normally absorbed by a freeze-resistant water mix, which can then be used to heat domestic water. Our collectors are angled at 30% to maximize solar heat gain.

The operation of the solar collector is very simple.
Solar Absorption: Solar radiation is absorbed by the evacuated tubes and converted into heat.
Solar Heat Transfer: Heat pipes conduct the heat from within the solar tube up to the heater.
Solar Energy Storage: Water is circulated through the heater. Each time the water circulates through the heater the temperature gradually raises.

Green Wall

The green wall is planted with three types of non-invasive plants:star jasmine, coral honeysuckle, and tangerine cross vine. The last two vines are native to the southeastern United States, and all require very little watering. However, they still need some watering attention to become established. Once our green wall is mature, we are not sure if they will be able to maintain their health without being watered minimally due to the size of the planters. Based on how they fare, we may recommend use of drip irrigation. The green wall will provide passive cooling to for the house, as well as a pleasant environment for the front porch.

SHADE STRUCTURE

The shade structure was designed to proivide shade for the light core and porch. Shade study models were produced to determine the right amount of shade needed, which informed us of the number, size, and frequency of louvers required. The shade structure is made out of powder coated steel, and provides approximately 75% shading for the light core.