Applied Research and Innovation Services

Net-zero energy retirement: Part two

Net Zero Energy Home


Lance Olson and Wendy Wright are building their dream net-zero-energy retirement home, Pelican Perch, with the GBT research team.

To save water and electricity, the couple was interested in the idea of a composting toilet. To learn more, they and project lead Rebecca Davidson met with John and Laura Kolk. The Kolks built a straw-bale home in Picture Butte, Alberta, where they have lived for three years. Some of the many eco-friendly features of the home include polished dirt floors (which have the appearance of polished concrete) a solar chimney (which works through a stack effect, ventilating and warming the home), four-foot wide straw-bale load-bearing walls and a wind turbine.

“What we learned from the Kolks is the composting technology for toilets is still in development,” explained Davidson. “The Kolks pursued the technology in an effort to save water and reduce energy in waste treatment and conveyance. However, because of difficulties encountered during troubleshooting, such as overflowing toilets and costly replacement parts as well as poor customer service, they opted for a toilet system similar to an RV or cabin, which is emptied manually.”

The Kolks advised that homeowners considering a composting toilet do ample research. Some composting systems deal with solids and liquids separately while others combine them within one compartment. Issues with overflow and broken composting-system parts can also occur.

With lessons learned from the Kolks, Davidson and the GBT team are researching eco-friendly sanitation systems for Pelican Perch. The system could include using rainwater collection for flushing, combined with ultra-low flow toilet fixtures. More decisions will be made as the design progresses.

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John and Laura Kolk built their eco-friendly straw-bale home in Picture Butte, Alberta. Photo credit:

John and Laura Kolk built their eco-friendly straw-bale home in Picture Butte, Alberta. Photo credit:

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