GreenTown Los Altos

Deep Green


Jun 2017


The “greenest house in America.” That’s what we heard at GreenTown’s lunch at Tah Mah Lah, the Holland-Yates home in Portola Valley. The home, designed to showcase the latest innovations in sustainable design, does that by being highly efficient, producing more energy than is consumed, restoring habitat, saving and repurposing water, and reducing and even reusing waste.

The lunch was a GreenTown auction item at last year’s Farm-to-Table dinner. The winning bidder and her guests heard from Tom Klope, landscape architect for the project. Klope explained that the design work began in 2006 and took many years. The team of architects and designers ventured into a number of new areas, leading to inevitable delays as the approval process had to catch up. According to Klope, this wasn’t necessarily a bad thing, as innovations in sustainable design are evolving rapidly. The house was completed in 2012.

Tom Klope describing the home’s design process

A few interesting highlights –

  • All of the material is recycled except the glass.
  • The Western Yellow Cedar used both inside and outside the home was sourced from another structure.
  • Everything is sourced within 500 miles with one interesting exception, the limestone. That came from Minnesota, but the carbon footprint of bringing it that far by rail beat trucking similar material from a quarry near Yosemite.
  • The home is energy-efficient and the solar panels provide enough electricity to make it more than net zero. 

    Tom explaining the geothermal heating and cooling system

  • The location of the home on the site and even its angle to the path of the sun was optimized to produce peak solar performance.
  • Rain is collected and stored in a 50,000 gal tank.
  • Gray and even black waste water is processed on site and used in the drip irrigation system.
  • The plants survived the four year drought.
  • A green roof was considered but the extra construction needed to support it did not justify the benefit.
  • A stainless steel roof was selected, but that required a two year test to convince the building department folks that it would not create an unacceptable mirror-like effect.

A view of the home’s solar installation

One goal, personally important for Klope: “Make it beautiful.” He planted all natives and the grasses are a blend of natives sold by Delta Bluegrass. They have different blends for different niches. You can visit Portola Valley and see six of the different blends planted in a field near Town Hall.

Sustainably built with attention to every aspect of a modern, green building. Now that’s a vision GreenTown can support!

To read about the home, visit

Written by Gary Hedden

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