potable rainwater collection system
The potable rainwater collection system is the first in the modern era in the city of Charlottesville. The water is collected using a single wedge shaped roof, which allowed the design team to cover both the house and rear porches, and direct the water into a single gutter, and a side-by-side pair of oversized downspouts – collecting all the water in one place. The roof water is stored in two 1,750-gallon tanks below the front deck, and a sophisticated filtration system located just inside the entry door provides clean water to the entire house. The system, sold as components to us by Rainwater Management Solutions, is the first of its kind in the city of Charlottesville. It provides roughly 35% of water needed in a year for a family of four. The system did not operate properly at first (due to some plumbing installation problems) and potential buyers of similar systems are encouraged to get a warranty for both parts and labor, and to use a plumber familiar with these systems.
solar hot water heater
The solar hot water system used on ecoMOD1 is a conventional flat plate system with antifreeze running the plumbing, so the pipes don’t freeze in the summer. The collected in the system is transfer to the domestic hot water, and also stored until used. The system reduces the water heating costs for the occupants by $300 to $350 a year. Initial problems with this system were resolved by the subcontractor that installed it.
daylighting
Each room has at least two windows on two different walls to allow natural light to illuminate the interior spaces. Effective daylighting can reduce annual energy costs by 20-30% and the layout of the house gives important primary spaces more sunlight.
structural insulated panels
The structural insulated panels (SIPs) used for the walls and roof are made of two layers of oriented strand board with a core of expanded polystyrene foam. The supplier was R-Control in northern Virginia. The system creates super-insulated walls and a roof, and structurally they are stronger than conventional stud frames. Buildings made with SIPs can be ‘framed’ is a shorter timeframe than normal stud framing, and air infiltration and thermal bridging are reduced.
energy star appliances
To help the homeowner save on utility bills, the design team selected all energy star appliances. The Energy Star program was created by and is managed by the Environmental Protection Agency, and the U.S. Department of Energy, and continues to evolve each year.
low / no-VOC interior materials
VOCs are volatile organic compounds found in paints, varnishes. sealants and primers that can impact indoor air quality and potentially harm the health of the home’s occupants. The ecoMOD teams try to avoid interior materials with VOCs whenever the budget allows it. The interior paint, caulks, sealants and flooring finish were all no or low-VOC products. The team could not afford entirely VOC-free cabinetry.
sustainably harvested wood floor
The flooring is from sustainably managed forests in Virginia. Bamboo was eliminated because of the embodied energy of shipping it from China. The species is poplar, a wood species found throughout the mid-Atlantic region of the U.S., and a relatively soft wood not always used for floors. However the budget was very tight, and poplar was the only affordable choice at that time. The wood is from the Sustainable Woods program of Appalachian Sustainable Development (ASD), an organization dedicated to the support of local economies and sustainable forest management. Appalachian Sustainable Development is part of the Sustainable Woods network, and uses standards designed to ensure long-term diversity of the forest and protection of water resources. These standards are very similar to the principles of the Forest Stewardship Council (FSC) and in 2009 (after the project was finished), ASD became an official FSC supplier. The ASD drying kiln, located in southwest Virginia, is solar and wood waste powered.
ecoMOD2, the preHAB house,
• contemporary design, environmentally responsible strategies and prefabricated construction within the constraints and mission of Habitat for Humanity. The goal is to create a house that is adjustable to the climate and weather conditions of southern Mississippi. Contained, exterior spaces are an integral element of the design, expanding the apparent size of the house, while helping to passively cool it. These spaces will incorporate elements that are able to both shade harsh sunlight and adapt to become hurricane protection devices.
• utilizes natural ventilation and the selective use of natural light,
• the intention with the preHAB house is to make an efficient, modest house that feels larger than it actually is.
• The house incorporates a photovoltaic solar panel array and a heat pump / heat recovery system that will provide domestic hot water. The design can be pre-fabricated as panels, modules, or both.
• The house is built from an innovative steel and foam panel, which is highly energy efficient, and resists hurricane force winds, as well as mold.
Envisioned as a contemporary structure, the project provides a highly flexible modular prototype that can be added as an addition to any home. The design explores the concept of the ‘seam’ between new and old, occupants and care providers, and inside and out, while simultaneously incorporating the principles of universal design.
ecoMOD3
The historic house, which is the focus of this renovation and addition project, is believed to have been originally built by a freed slave or as slave quarters.
• built in four phases spanning from the early 1860’s to the 1970’s.
• Through the historic preservation effort, great attention will be paid to designing for deconstruction, as well as the potential for material reclamation, refurbishment, and reuse.
• Additional design features include an evacuated tube solar hot water system coupled with on-demand water heating, a modular green roof system, and ThermaSteel wall panel construction.
• As a component of the universal design agenda, the seam house will employ a medical monitoring system while following ADA guidelines for accessibility.
The concept of modularity also extends into the landscape with the notion of the ‘seed packet’ – a tool for assessing and deploying a set of predetermined elements based on existing site conditions. In addressing these issues, the seam house system also complies with LEED for Homes sustainability criteria.
Landscape and building combine and negotiate elements of climate and city to not simply connect site and structure, but to allow residents to engage their environment and society. The many permutations create a comprehensive strategy for turning site into place and room into home.
ecoMOD3 accessory unit
daylighting
mechanical systems
mini-split heating and cooling system. The highly efficient system is duct-less, reducing the potential of indoor air quality problems. A passive air inlet and continuously running low CFM bathroom fan ensure fresh air is regularly renewed in both housing units. The overall system is less than have the cost of a conventional heat pump system, and the variable speed fan helps keep the system efficient.
Design for deconstruction
Landscape
A small garden at the front of the historic home is meant to collect some water; the gravel courtyard between the housing units and the green roof on top of the modules are designed to collect water and allow it to either percolate into the soil or evaporate into the air. The lowest part of the lot, behind the accessory rental unit is a fully engineered rain garden, with water loving plants to collect any water that makes it that far. The plants are all native and drought tolerant.
green roof
The prefabricated modules of the ecoMOD3 project–the modular bedroom added to the historic house, and the accessory rental unit–have a tray (modular) green roof system provided by a Virginia based company, Building Logics. The design aims to reduce site runoff and insulate the house. It is a relatively affordable green upgrade and fits into the modular agenda of ecoMOD. The system is composed of a roll applied waterproofing membrane in combination with pre-grown trays that allow for negligible maintenance for the homeowner post-installation. Each tray was planted with a wide variety of hardy sedum plants that, once installed on the roof, began to adapt and certain species became dominant according to climate conditions.
universal design
evacuated tube solar hot water
passive design
While active mechanical systems and appliances are connected to the city grid, consuming utilities such as electricity, gas and water, passive design relies entirely on readily available natural resources like the sun and the wind.
LEED for homes
the project’s conscientious design and construction decisions. The project received a platinum rating, the highest available within the system. The location of the housing unit, in the city, near public transportation and other community resources contributed to the high rating.
ecoSCREEN
The team designed a steel trellis / shade system for the deck of the accessory rental unit called ecoSCREEN. It provides a seating area, a protected threshold, and a framework for vegetation. The screen addresses many issues that are integral to the seam house design, supporting the mobility of an aging client, transitioning between indoor and outdoor spaces, and providing a modular structure that easily adapts to a variety of site conditions.
monitoring
The ecoMOD3 engineering team designed a comprehensive, feedback-based energy monitoring system for the project that would allow temperatures, humidity, and carbon dioxide levels to be monitored throughout the house. A wireless system, data is transmitted wirelessly from each sensor to a central base station. The system is based on an intelligent electrical monitoring system that determines specific appliance usage in the house by only monitoring the three main power conductors in the circuit breaker panel. The homeowners initially expressed some concern about having information about his daily patterns accessible to others, and so the team only installed the solar hot water monitoring components into the home. The remainder of the system was installed into ecoMOD1, to allow the new wireless strategy to be directly compared to the fully hard-wired system, and determine if the information it gathers is comparable. So far, the data correlates successfully.
medical monitoring
The energy team also developed a simple, non-invasive home medical monitoring system that records patient vital signs–the original concept of the SEAM design was to make the housing unit available to people that want to ‘age in place.’ The team researched housing for elderly, working with the Jefferson Area Board on Aging and the UVA Institute on Aging. However, the homeowner is not elderly and is sufficiently healthy to not require the medical monitoring system.
• ecoMOD4 thru
• 1,100 square foot in Charlottesville. Features superinsulated building envelope, grey water system, geothermal heating, and solar panels. Consumes 60% less energy than a typical home.
• $150,000
• insulation
• The first step in designing a highly efficient housing unit is to insulate the house as well as possible. In the case of ecoMOD4 we decided to aim for the Passive House standard, which recommends a certain amount of insulation. Although some forms of installing insulation have unintended environmental impacts, over the life of the building, the environmental savings will more than make up for the negative impact. We used a combination of open and closed cell foam. Closed cell foam has double the resistance to heat flow, but also double the cost. We used closed cell in the roof, getting an R-value of over 60 (code requires R-20 in new construction) and open cell in the walls with an R-value of 30. Creative Conservation installed the installation.
• insulated concrete formwork (ICF)
• The basement / foundation of the home is constructed of insulated concrete formwork (ICF). ICFs are essentially oversized hollow core blocks made of expanded polystyrene foam insulation. The are built like a concrete block wall, with steel reinforcing running both vertically and horizontally, and the core are filled with poured in place concrete. The resulting construction is both incredibly strong and very well insulated. AMVIC and Allied Concrete provide the material at a discount to demonstrate the technology to Habitat for Humanity.
• energy simulations
• The ecoMOD4 team worked closely with faculty in architecture and engineering to develop accurate energy simulations that could influence the design process. The house was modeled using Google Sketchup and Energy Plus, both free publically available software packages from Google and the U.S. Department of Energy respectively. The software allowed us to predict seasonal energy usage and comfort levels from a variety of inputs such as wall construction, window size and placement, occupant activity, and passive ventilation strategies. In addition, the ecoMOD team used these energy modeling tools to determine the correct size and orientation of our rooftop photovoltaic array. We were able to simulate power output based on weather data collected in Charlottesville and compare that with predicted hourly electric loads in the house to effectively design the system for our specific needs.
• geothermal heating and cooling
• After insulating the house, orienting the home to take advantage of the positive aspects of a climate zone, and using the most efficient windows you can afford, the next step to reducing your energy load is an efficient HVAC system. By far, the most efficient is a ground source heat pump – often referred to as geothermal system. Unlike a standard heat pump that exchanges heat with the air outside of the window — so efficiency varies with the outside temperature — a ground source heat pump exchanges the heat with the much more constant and predictable ground temperature. The expected combined heating and cooling costs for ecoMOD4 are expected to be under $500 a year.
• domestic greywater system
• It makes little sense that the water used to flush the toilet should be just as clean as the water we drink from the tap. With that in mind, ecoMOD4 has a small, inexpensive greywater system that takes the wastewater from the bathroom sink and reuses it in the nearby toilet. It is estimated to save nearly 5,000 gallons of fresh water per year, and requires little maintenance. We decided against a full house greywater system because of the significant upfront cost. The system fits under the bathroom sink, and costs less than $250
• manifold
• The standard plumbing in a house runs a single line from the hot water tank to the furthest fixture, branching off from the main line at any intervening fixtures. To save energy, we used a manifold system. A manifold is a short length of pipe with one entrance and multiple exits. The manifold is located a few feet from the hot water heater. By running smaller pipes from the manifold to the fixtures, a significant amount of energy is saved. The volume of water in a ½” pipe is half of that in a ¾” pipe. In ecoMOD4, this system saves over 5000 gallons of hot water per year, and the energy required to heat that water.
• desuperheater
• The waste heat from the geothermal heat pump is typically released into the ground. During the summer, ecoMOD4 employs a desuperheater to transfer that waste heat to the hot water – effectively reducing the water heating energy load during that season. Although the savings is not that significant in the mid-Atlantic climate zone, the upfront cost is minimal.
• interiors
• The interior of the home is designed to emphasize the relationship between the inside and outside. Affordable and durable IKEA cabinetry is mixed with custom cabinetry to provide sufficient storage space and reinforce the design ideas. Low-VOC paints are used throughout, and the team found inexpensive, discontinued bamboo flooring – recognizing that despite the rapidly renewable aspect of bamboo groves, there is a large carbon debt from shipping the flooring from China.
• photovoltaics
• Some of the electricity used in the house is produced by a rooftop photovoltaic (PV) array, consisting of 4kW PV polycrystalline silicon panels installed by Solar Connexion of Blacksburg, Virginia. The system is connected to the utility grid, and the team is monitoring the energy production.
• landscape design
• The ecoMOD4 house was built upon a previously developed brownfield–a parking area, doghouse and shed with a lot of concrete and other construction debris underneath–which required large scale site remediation to restore the land as a buildable site. The landscape design focused on two main strategies: collecting and managing stormwater runoff and using native vegetation to define exterior spaces. Material and plant choices closely follow the sustainable site guidelines set out by LEED for Homes. The hardscape materials (in part, crushed recycled concrete) were chosen to be permeable, light in color and are shaded in order to reduce the heat island effect on the site. A variety of native grasses and plants serve as natural and layered screening elements to ensure privacy along the site’s busy street.
• stormwater management
• As a new home, ecoMOD’s roof and hard surfaces decrease the area available to absorb stormwater before it runs into neighboring yards and the local watershed. This increase in stormwater runoff can disrupt ecosystems, overwhelm streams and rivers, and contribute to pollution. The ecoMOD landscape design minimizes and stops water from running off of the site. Using permeable surfaces on the drive and walkways, collecting roof runoff in rain barrels and directing yard runoff through a swale towards a rain garden, the stormwater design minimizes environmental impact in a manner that is affordable.
• bamboo flooring
