Energy Efficiency from the Ground Up
1999 Switzer Fellow Erika Zavaleta strives to bridge ecological theory and research to sound conservation and management practice in her work and personal life. Between 2008 and 2010, she and husband Bernie Tershy worked with Anni Tilt of Berkeley-based Arkin Tilt Architects and Santa Cruz builder Marc Susskind to design and build a home that did just that. The home won the Best New Home award from Fine Homebuilding Magazine.
Erika wrote a short piece for us about how the process of designing and building their house made her aware, maybe more than anything, of how closely tied the comfort of a structure is to the same energy design elements that make it efficient. She says, "When we sell energy efficiency, we usually focus on environmental and/or economic arguments. But for passive innovations that manipulate solar gain, thermal mass, and airflow, comfort is the best selling point, and we should talk about it more."
To learn more about the home, check out two articles about it in local media, one about the Fine Homebuilding Award and the other about the playful spin the house puts on environmentally conscious design (with photos).
The process of designing and building our house made me aware, maybe more than anything, of how closely tied the comfort of a structure is to the same energy design elements that make it efficient. I highlight this because it was a pretty unexpected lesson; our house is 68-72 degrees all the time and everywhere, and not because we’re running air conditioning and heating all the time. This is a feature that I had no idea I’d appreciate so much. This past December, a week after we finally pulled out and sold the high-efficiency wood stove that we had installed and never once used in two years, I ate lunch in my winter coat at a downtown restaurant, drove home shivering, walked through my front door and got barefoot and t-shirted. The bale walls and thick concrete slab store and re-radiate the heat coming in the south windows; the double windows don’t let in drafts; the modest heating from the radiant floor system warms our feet and rises up through our open floor (and ceiling) plan. In summer, the roof overhangs keep the south shaded; we can open high windows to let the heat rise away; and the concrete slab and bale walls pull away the day’s heat. It is 68-72 degrees, all year long.
When we try to sell the benefits of energy efficiency, we usually focus on environmental and/or economic arguments. But for passive innovations that manipulate solar gain, thermal mass, and airflow, comfort is the best selling point, and we should talk about it more. Some of it is also relatively simple; many think of energy efficiency in terms of solar panels, heat exchangers, and just generally being uncomfortable (i.e. braving the cold and heat). The single biggest energy efficiency feature of our house is that we paid attention to where the sun shines and the wind blows – most of the windows face south, the south walls are thinner (board-and-batten), the yard faces south and is sheltered from the prevailing northwest winds by the house. The north walls are thick and insulating, with few windows and less surface area (thanks to the angled roof). We have some high windows to let out heat and a roof that shades out the sun in summer but not in winter. If new homes did just that much and nothing more, they would be both more energy efficient and more comfortable with no change in cost or need for expertise.
Other features, like solar panels and a highly efficient air-to-water heat exchanger, don’t necessarily pay for themselves and take more work, but this would change with better policies (such as tax breaks and incentives) and the larger markets that would emerge as a result.
Having said all that, I think that we have this house we love so much in part because energy efficiency wasn’t the dominant goal. People have different visions of what “family” means in practice, and we had the great fortune to work with architects who got that. For example, for us it meant putting connection over privacy, both within the house and between us and the surrounding community. The flow of our house reflects this deeply. We also had goals about enhancing the landscape and neighborhood even though we were putting a house in it, linking indoors and outdoors strongly, using local and personal materials (my husband’s childhood beach glass collection in the floor; driftwood and reclaimed redwood and douglas-fir everywhere), having a small physical footprint (the house covers 21% of our urban lot), and creating a space inviting to extended family, aging parents, and our future adult children. All these things give the place soul and make it work for us. The way that our architects, Arkin-Tilt, integrated and worked with us on all of these pieces is a critical model for ecological design – it has to be about an array of holistic goals, of which efficiency and environmental performance are only one piece.