Dirk Ellis had a vision. While pursuing a career as a commercial pilot, Ellis dreamt of opening a unique business in Montana’s Helena Valley. After researching several ideas, he saw a need for an organic coffee roaster and shop similar to his brother’s (Strawhouse Coffee in California). Continuing with his research, Ellis came to believe that there was a need for a full-service natural food market that would funnel business to an organic coffee roaster. His idea blossomed into a full-scale natural food store with a deli and coffee shop.
While looking for the ideal location for this business, it was brought to Ellis’ attention that a new mixed use development was going on in an area on the north end of Helena that previously was mired with dredge tailings. The developers had taken an eyesore and were in the process of designing a neighborhood with green spaces and walking access to schools and shopping centers.
“I saw this as an opportunity to build a new building without cutting down trees to build a parking lot, so to speak,” said Ellis. “The developers were open to our idea of the store and made available the south-facing lot we needed and even went to the trouble of dividing the lot to an affordable size. All this pointed to the necessity of some kind of construction that could convey the principles of what we wanted to make available to the community. Something my heart and soul would be involved in and worth the financial risk.” It was at this time that Ellis decided to build with straw bales, a model that he knew had worked for his brother’s store in California.
Now the hard work was about to start as the proposal of an 8,500 square foot straw-bale commercial building within city limits had to be sold to both the lenders and the city planning board, as well as finding an architect who would be willing to design the structure. “During this time I felt it would be best if a straw-bale expert was brought into the project mix to answer questions for the architect and present this form of construction to the city,” said Ellis. “This is when Jeff Ruppert and his team at Odisea Inc. came into the mix.” With over nine years of experience building residential straw-bale structures, as well as engineering many around the Rocky Mountain region, Ruppert and his crew were able to provide the straw-bale expertise necessary to move this project toward completion. Ruppert wore many hats for Ellis on his project, providing the structural engineering, overseeing the straw installation and stucco finish, and leading a bale-raising workshop for interested community members. “I feel that his involvement was paramount in giving everyone the confidence to move forward,” a grateful Ellis remarked.
After having successfully navigated his way through the design development and construction document phases, Ellis decided to revisit the mechanical heating and cooling systems. “The systems incorporated into the building by the local engineers just did not have the forward-thinking designs that I felt were needed by a building of this nature,” said Ellis. “The baled-straw system set the design apart from the ordinary and deserved the integration of systems that reflect the intent and would enhance the building performance. I felt that the overall look and feel characterized by the baled walls possessed and conveyed the natural, unique long-term architectural solutions I was looking for. Therefore, any systems being applied to the building needed to enhance those virtues.” The mechanical redesign resulted in the integration of a ground source heat pump, photovoltaic panels that doubled as overhangs to optimize the passive solar qualities of the building, and an integrated rain harvest system.
With an anticipated opening date of late January 2005, the StrawHouse Market is already looked up to as a gleaming example for environmentally conscious construction in an area surrounded by incredible natural beauty. Glancing back upon the path which has brought his dream to fruition, the soon-to-be entrepreneur Dirk Ellis is satisfied. “I guess I would have to say that I did not start out to build a building that pushed the envelope of sustainable building. It just turned out that it all made sense in the end.”

Building Details
The StrawHouse Market is post-and- beam construction with baled straw insulation, setting it apart from the surrounding box stores of Helena’s northern commercial district. In addition, the building has incorporated a synergistic integration of interdependent energy saving systems, further staking its claim as a building that rises above its peers. Passive solar design, photovoltaic power, a ground source heat pump, and a rain/snow harvesting system are some of this building’s progressive features.

Passive Solar
Passive solar gain is accomplished through 165 square feet of fenestration at the south elevation. Overhangs prevent the floor slab from receiving direct solar gain in the summer months while optimizing the heating of the slab through direct solar gain in the chilly winter, thereby achieving a “timed release” of heat conduction from the floor to the interior air across late afternoon and evening periods. An arching south wall accentuates the sun’s penetration in the late afternoon. Models predict that this design should account for 20 percent of the heating requirements for the building. Glazing was minimized at the north, east, and west elevations in order to prevent heat loss and to eliminate direct sunlight on merchandise and equipment.

Photovoltaic Power
Grid-tied photovoltaic power generation offers two major benefits over stand-alone systems: since no battery is necessary, they reduce the first cost of the system, and in the presence of net metering laws like those in Montana, grid-tied arrays allow the ability to abate a building’s energy consumption at full consumer rates when site generation exceeds consumption. Factoring in the 30-year design life of the photovoltaic system, it is expected to save over $75,000 in electric utility bills. Considering the system’s price tag of nearly $48,000 (after Montana tax credits), that the PV panels are anticipated to exceed their 30-year design life, and with the era of cheap energy drawing to a close, onsite energy generation using an alternative to conventional fossil fuels adds up to a wise investment.

Ground Source Heat Pump
The heating and cooling needs of the StrawHouse Market are complex. Combining grocery retail with cooking facilities offers a challenge to providing for both kitchen conditions and a perishable inventory. Compounding this hurdle is Helena’s climate, consisting of brief, cold winters interrupting extended, milder seasons. A system to meet these needs was chosen, employing a ground source heat pump (GSHP) combining geo-exchange with small variable air volume (VAV) heat exchangers. This system is able to capitalize on the constant ground temperature to serve both the building’s heating and cooling needs without the increased costs of adding more ducting and upsizing the system, as would be required in conventional HVAC systems. The efficiency of the GSHP should result in heating cost reductions of 40 to 70 percent compared to conventional systems and as much as 50 percent for cooling. These figures would result in a system payback from three to five years.

Rain Harvest
With 11 inches of annual precipitation, the roof intercepts in excess of 51,000 gallons of water. This water is directed across landscaping for both irrigation purposes and to allow planted areas to help treat and retain storm water runoff. A site scheme incorporating permeable paving combined with strategic grading to lead all runoff to planted areas accomplishes the aforementioned tasks.

Derek Esposito is pursuing a masters degree in sustainable building at Colorado State University. While living in Helena for a few months this past summer conducting research for his thesis, he spent many afternoons stacking bales on this project.
For more information, go to www.strawhousemarket.com