Design Green Design Earth Tubes: Low Tech, Low Energy By Lloyd Alter Design Editor University of Toronto Lloyd Alter is Design Editor for Treehugger and teaches Sustainable Design at Ryerson University in Toronto. our editorial process Facebook Facebook Twitter Twitter Lloyd Alter Updated October 11, 2018 Migrated Image Share Twitter Pinterest Email Design Tiny Homes Architecture Interior Design Green Design Urban Design Brian Jonas at Greenline, the great sustainability blog from Ziger/Snead Architects, shows a great picture of an earth tube being installed at the Aldo Leopold Legacy Center. Earth tubes are the dead-simple way of bringing fresh air into a building at a reasonable temperature- just run the air through pipes buried in the earth, cool in summer and warm in winter. Result: it comes out at a nice, comfortable temperature. Unfortunately it is a nice temperature for mildew and bacteria, not to mention a great place for animals to nest; Brian notes that "Ductwork or pipes rated for underground use are employed, the ducts must slope to drain to avoid water and mildew build-up and additional filtration is sometimes required to eliminate mold and bacteria." Radon buildup can also be a problem, so they need to be tightly sealed. ::Greenline, good Wikipedia coverage too.