Tah Mah Lah

2021 All-Electric Leader
Honorable Mention

Location: Portola Valley

Building type: Single family home, new construction

Status: Completed

Size: 5,600 square feet

Completed: 2011

Owners: Paul Holland and Linda Yates

Website: www.tahmahlah.com

Contact: Linda Yates (linda@mach49.com)


Tahmahlah is an exciting summary of what building green can aspire to be, covering every dimension of sustainable design — energy, materials, water, waste, and habitat. The home is designed to zero net energy (ZNE) standards and, with addition of electric cars, is operating at near net zero. It has a super-efficient enclosure and 100% all-electric services: HVAC, domestic water heating, cooking, and clothes drying, fueled by both solar and geothermal sources of energy.

The home is fossil-fuel free and is exemplary for how residential buildings can help protect Bay Area air quality. Beyond net zero energy, the goal is for the family to have a net zero carbon footprint including transportation. Even the homeowners’ cars are electric. A major goal of this project is to inspire others to build green by debunking three myths: that green homes can’t be beautiful, that green buildings are twice as expensive, and that raising a family in a green home requires a drastic change of lifestyle.

Special Features

  • 27 kW solar photovoltaic system
  • Heat pump water heater
  • Geothermal ground source heat pump
  • Radiant heating
  • Induction cooktop
  • Daylighting and shading
  • Conscious siting of the home for maximum solar exposure
  • 100% recycling of all gray and black water + 35,000 gallon cistern (as a major consumer of energy, conserving and recycling water also reduces energy requirements)

Project Team

HKS/Hill Glazier Architects
Integral Group
MGM Construction
Evolution Construction
Ann Edminster
Bruce King
Peter Rumsey
Tom Klope
Patrick Kobernus