Learning to live green

When Beatrice Briggs decided to build a house and yoga studio near Tepoztlán, Morelos, she wanted a home that would reflect her "own ecological values, [and her] desire to make something that would be beautiful, comfortable to live in, and could serve as an inspiration to others."

She sought out architect Michel Lewis, a team of solar experts, and water systems designer Art Ludwig. Together, they built a large (4000+ square feet) structure that, in spite of its dimensions, has a minimal impact on its environment.

Her home, named Huehuetortuga (Nahuatl for the "old, old turtle"), exemplifies the opportunities-and occasional compromises-involved in sustainable building. The house is situated on the southern slope of a hill: this exposure, along with the region's mild climate (ranging from 24 to 32 degrees Celsius) makes heating systems unnecessary: skylights allow solar energy to enter and be absorbed in adobe walls, which release heat at night.

In addition to locally-made adobe bricks, construction materials included stone found on-site, recycled red roof tile, and non-endangered hardwoods sealed with linseed oil. Slate from Taxco was used for the terrace. The natural building supplies mean that Briggs's home is free of chemicals found in synthetic materials.

Electricity is provided by twelve photovoltaic solar panels on the roof. The energy is stored in batteries, and supplemented during the June-October rainy season by a water turbine, which has "kept the lights on during two weeks of cloudy weather," according to Briggs. The state power grid and a gasoline-powered generator exist as seldom-used backup systems.

Water was a major concern. This part of central Mexico averages 1,400 millimeters of rain per year, but most falls during the four month rainy season: drought conditions prevail the rest of the year. Water designer Ludwig created a system of two cisterns: a 50 cubic meter tank behind the house fills with rainwater and is fed by a nearby seasonal waterfall. It supplies the solar hot water heaters and the cold-water faucets in the house. A secondary 25 cubic meter unit is replenished by runoff from the roof, and feeds the kitchen and laundry areas.

Water is conserved through the use of low-flow fixtures and a composting toilet (there are six-liter low-flush toilets available as well). Because bathrooms and the kitchen are far from the hot water tank, Ludwig designed a system of pumps to circulate the water as it heats, avoiding waste and time spent waiting for it to warm up. Wastewater from the flush toilets is treated and eventually ends up in a constructed wetland, while gray water is used to irrigate fruit trees and plants.

Bea Briggs is proud of her home. It is very comfortable, though she admits that the finished result isn't perfect. Nonetheless, the systems at Huehuetortuga have served as examples for people seeking a more sustainable way to live. Briggs will see "some efficiencies and economies over the long run," but "the main return on the investment is the (on-going) learning process and the ability to show what is possible."

You can contact Beatrice Briggs at bbriggs@iifac.org.

To learn more about her house and sustainable development classes visit the website: huehuecoyotl.net