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Modest Size Design
Visitors may be surprised to learn that the Eco-Home has just over 2,000 square feet of finished space. That is small compared to many new houses built today, but its well-designed flow gives it the feel of a much larger home, while preserving precious natural resources.
The Eco-Homes's open floor plan and warm, inviting layout offer a bright and airy living environment suitable for a family. A bedroom, full bath and all family rooms are located within the 1290 square feet on the first floor. The 750 square feet second floor contains two bedrooms, one study, and a full bath.
Orientation for Use of Renewable Energy
The home combines passive solar design with active solar components (See Energy Efficiency) to maximize the power of the sun. The home is oriented on the lot along true north-south to take advantage of solar gain. The compact footprint, open living spaces, and design with utilities to the north and living to the south incorporate some of the best principles of passive solar design. Learn how a high performance building envelope and a passive solar design work together as one system on the Women Working website.
Orientation and design for daylighting
Daylighting strategies draw natural light into all rooms from at least two sides. The passive solar design considerations mentioned above are just a few strategies that can be applied to a design. Visit the Whole Building Design Guide for more information on daylighting strategies for the home.
Foundation
A frost-protected shallow foundation was constructed for improved accessibility (level entrance) and enhanced solar gain. The design also helped to reduce excavation costs and impacts associated with deep foundations or basements. It consists of a monolithic slab with 4-inch Polystyrene Extrusion Plastic Sheet (XPS), or XPS foam board, insulation under the slab and vertically around the perimeter to an R-value of 20. Also, 3-inch XPS insulation (R-15) was used to create the horizontal wing. The slab contains hydronic tubing for a radiant floor heating system (discussed in detail under Energy Efficiency).
Windows
The windows are manufactured of insulated fiberglass frames. The triple-panes are argon filled with warm edge spacers to increase the resistance to cold Minnesota winters. Low-e coating on southern windows reflects heat away in the summer and traps heat in during the winter while allowing daylight to enter year-round providing an efficient @solar heat gain coefficient (SHGC)@. The overall U-factor averages 0.2.
Exterior Wall Finishes
Fiberboard sheathing with recycled content was purchased from a regional producer, which reduces material use and energy use from transportation. Fiber cement board lap siding is a durable finish.
Roof
The home was capped with a durable standing seam metal roof made from recyclable steel. The metal roof and flashings were prefinished at the factory.
Finish Floor
Tile, cork and reclaimed wood flooring were selected for minimal environmental impact. The porcelain floor tile is long lasting, has low toxicity, and low impact material extraction. The floating Cork floor is a natural material harvested without killing the source tree.
Cabinetry and Trim
ShetkaSTONE countertops were made of pre- and post-consumer waste paper products. They are produced regionally, reducing energy use during transportation.
The cabinet interiors are made from formaldehyde-free medium density fiber (MDF), a recycled wood fiber with a non-toxic manufacturing process.
Other
Recycled content Cellulose insulation provides high R-values using low embodied energy.
Efficient Use of Materials
Exterior porches and interior columns were constructed with reclaimed timbers.
Products with Minimal Off-Gas
Casework was made from formaldehyde-free medium density fiberboard (MDF). No Volatile Organic Compounds (VOC) paints were used throughout the interior of the home.
Reduction of Textiles, Maximized Hard Floor Surfaces
There is no carpet within the home. Hard surfaces reduce the potential of off-gassing and allergens that may become trapped in harder to clean carpet.
Ventilation Design (related to climate conditions)
A mechanical ventilation system operates in the home. A sub-soil ground loop provides heat exchange during distribution. This works by using the nearly constant warm temperatures (during winter) of the ground to "pre-heat" cold incoming air. The system works in reverse, cooling incoming air, in the summer. That is if the ventilation system is in use rather than having the many windows open for natural ventilation.
Detached Garage (or attached with "advanced sealing")
A 2-car garage with a storage room is attached via breezeway. There is no common wall that might allow harmful pollutants to seep into the living space.
Harmful Gas Monitoring and Control
A sub-slab radon mitigation system was installed. Wiring was added to the attic to allow easy installation of a fan should radon levels ever rise in the home. The installation of this type of system is relatively inexpensive and easy during construction, but much more difficult as an add-in later.
Building Envelope
The building shell consists of 9.5 inch deep, double 2 X 4 stud walls. A densely packed cellulose insulation was installed to R-value 35. The structural fiberboard sheathing adds R-1.2 to the wall. The exterior was finished with a fiber-cement board panels.
A continuous 6-millimeter polyethylene sealed vapor barrier was installed beneath the interior gypsum board.
The attic boasts 16-inch energy heel roof trusses and cellulose insulation to R-60 to help alleviate ice dams and conserve energy. The standing seam metal roof has continuous soffit and ridge vents. It was finished with 30 pound felt and ice and water shield over OSB sheathing.
Insulated rim board with additional 3 inch closed cell (two-part) urethane foam (R-31 total).
Outstanding attention to detail of flashing and sealing was used during the installation of the insulated fiberglass windows to ensure an air- and water-tight seal.
Mechanical Systems
A 2 kilowatt (kW) grid-tied solar photovoltaic array is mounted on the roof. This system provides electricity to the home to offset energy use from the grid. Should extra electricity be generated, the homeowner will receive a credit towards existing use.
The distribution system for space heating in portions of the house is supplied hot fluids from a heat exchanger attached to the domestic hot water system (See Innovation Details).
The second floor (minus the bathroom) receives air warmed by the heat exchanger through the ventilation system. A sub-soil heat exchange ground loop pre-tempers ventilation air, reducing energy used to reheat or cool this air as it enters the home.
A small, efficient wood stove in the living room provides additional space heating for the open areas of the first floor. The addition of space heat on the first floor provides a "quick heat" option when occupants want a faster response time than the radiant floor typically provides. The wood stove alone is capable of heating the entire house.
Water Heating
The house has a "hybrid" design, where a combined system provides both heat and domestic hot water. It is a combination of very current technologies, high energy efficiencies, and renewable energy. The concept of "hybrid technology," using the on-demand water heater coupled with a solar domestic hot water system, makes this model worthy of the title "demonstration home." It is a reliable whole house system, without a boiler or furnace.
More detail on this system is available here. 
Appliances
All appliances were Energy Star certified appliances.
Lighting
All lighting met Energy Star lighting certification requirements.
Report performance data if available
The energy performance, ie. operating energy loads, were modeled and quantified using a computer based energy modeling program. The details of modeling and inputs can be viewed on the Women Working website. The result is that this home is estimated to require about 1/3 the cost of a house built to code. The actual performance of the finished home will be carefully monitored to compare real world results with the modeled performance predictions.
Exterior access
Access into the home's front door or garage requires one step up to the porch. Either entrance could be easily retrofitted with a ramp if desired.
General living space
One bedroom and full bath are located on the first floor making the home fully accessible on one level. The open design contributes to accessibility.
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