Lessons Learned

According to architect Ernesto Fonseca, who analyzed the project as part of his graduate thesis work at ASU and who was a member of the design/build team, the following lessons can be derived from the Nageezi House:

• High desert temperature swings are the ideal impetus to use thermal mass in the design.

• Passive heating can mean the difference between a high and a low energy bill, and between comfortable and uncomfortable indoor ambient temperatures.

• Passive strategies should be the first alternative implemented, followed by the optimization of mechanical systems.

• Good design does not necessarily have to increase the price of housing units.

• Sustainability targets long-term affordability.

Computer simulations run before the occupants moved into the house did not take into account some of the realities of life on the Navajo Reservation in a multigenerational setting. Before a washer and dryer were donated as part of the Nageezi House project, this family used solar power to dry clothes after driving a great distance to wash them at a laundromat. So, while the in-home washer and dryer added to their quality of life (and saved much gasoline), it also boosted energy usage above the predictions, and above that used in the previous home with no washer and dryer. Because the client's children live on either side of them, and no other family members have a washer and dryer, or even a hot shower, more people are using the home than the model accounted for.

Daniel Glenn, the Stardust Center design director who led the project's design, says the clients anticipated that a "new, green home may cost less, but you can't compete in low energy costs with a home where they heat one room with wood and cluster around it, and nobody is using a washer and dryer or taking a hot shower." Even with an efficient new home, in parts of the first year the occupants spent more on electricity because of the technological improvements and the fact that teenage grandchildren came to live with them for some months. The design team is working with the family to help them realize that while their living standard is now higher, their energy bills are also moderately higher because of the new amenities, a larger space requiring heating or cooling, and additional family members.

Passive Ventilation: Technology Versus Human Actions: The ventilation strategy depends in part on small, motorized windows that automatically open to allow additional cooling when needed. In the first months of occupancy, these windows did not work as intended. They had been improperly installed by someone other than a certified electrician due to budgetary constraints. Glenn sees the window mechanics as "good in theory, but a little worrisome in practice. Anything mechanical can break—will the occupants be able to afford to replace?" He thinks a backup manual system might help if it could include an easy way to access the windows, which are located high up in the walls.

The longer learning curve required for the radiant floor heating system proved challenging in realizing the anticipated energy performance. The occupants had previously heated their home exclusively with wood. In the winter, they would huddle around the wood stove while the other rooms remained cold, or put out the fire when it got too hot inside. Radiant heating, however, works on the premise that it gets cold in November and stays cold until May. The occupants began to shut it off when it got too warm, causing the slab to cool down, which then required a great deal of energy to heat it back up. Needless to say, initial performance was below expectation for the first couple of months until the homeowner learned how to properly operate the system. A highly efficient wood stove may have provided better heat in this case, although the family requested that it be omitted in favor of a fire pit, which was built in the hooghan patio and is used a great deal.

The long-distance monitoring system allowed the design team to provide feedback quickly. For example, when the house got too warm, the team was able to call the client's next-door son and ask him to open his parents' window.

Looking Forward: What's Next: The team is already applying what it learned from this project to several others. The Stardust Center recently signed a contract with Indigenous Community Enterprises (ICE), a nonprofit on the reservation that builds housing, to reproduce the working drawings based on the Nageezi home into two-, three-and four-bedroom models. ICE hopes to take the best of the Nageezi House and simplify the design where possible. For example, creating a hooghan-shaped courtyard using a material like FlexCrete is challenging, because it requires skilled carpenters to interlock the blocks at 45 degrees. The designers are investigating the idea of pouring corners and inserting straight blocks between them to make the construction less complex.

Lessons from the Nageezi have also been applied to a second house using the same materials in a different climate. The Guadalupe House is being built in the small, century-old community of Guadalupe, Arizona, near Tempe. Like the Nageezi House, this home design also focuses on sustainable, culturally responsive housing, this time addressing local Mexican American and Yaqui Indian culture. (The community of Guadalupe was founded by Yaqui Indians from Mexico.) The Guadalupe House also uses locally sourced Navajo FlexCrete blocks and small-diameter timbers from the Navajo Reservation in northern Arizona. A small Navajo-owned start-up, Southwest Traditional Homes, provided logs that would have otherwise been mulched or burned as a waste product.

The Stardust Center used a workshop process to generate the design, gathering input from locals familiar with the culture and from community representatives who provided input about their needs. For example, adult children and their families often live in their parents' home, so multigen-erational homes are desirable. The process also reacquaint-ed the participants with traditional native building approaches still common south of the border in Mexico. "In both projects," says Glenn, "the effort has been to create homes that are responsive to the regional climate as well as to the specific culture for which we are designing. We have learned from these projects that these two aspects of culture and climate are integrally related. Our challenge is to create modern homes that strive to come close to the extraordinary symbiosis of climate and culture that is inherent in indigenous dwellings."

ASU student Adrian Holiday comes from Kayenta, Arizona, and was an integral member of the student design/build team for the Nageezi House. About the project, he said, "It was quite an experience learning about my culture. We forecast that other students will follow us. To express our culture in these structures, it's beautiful."2

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