O’Neill Passive House

An image of the retrofitted O'Neill ranch house.
We liked the fact that the units are so compact — the outdoor unit’s the size of a suitcase.

Catherine O’Neill retrofitted her 1960s ranch house in Sonoma, California, with the goal of showcasing energy efficiency. When it came to choosing a cooling and heating system, meeting that goal meant installing ductless from Mitsubishi Electric. The selected system was able to meet the home’s small cooling and heating loads, and additionally offered quiet operation. The result: O’Neill’s home is not just a comfortable place to live, but the first Passive House in California and the first Passive House retrofit in the entire country! Download the PDF below to read more. You’ll hear from the homeowner, architect and Passive House consultant, and see photos of the home and equipment.

O'Neill Passive House

Project Location: Sonoma, California
Completion Date: October 2010

Project Team

  • Owners: Catherine O’Neill
  • Architect: Signum Architecture, St. Helena, California
  • Builder: PassivWorks, Inc., Vineberg, California
  • Passive House Consultant: Essential Habitat, Fairfax, California
  • HVAC Engineer: Path2PassiveHouse, Berea, Ohio
  • HVAC Contractor: Accell Heating and Air, Napa, California

Mitsubishi Electric Equipment Installed

  • (1) MUZ-GE12NA Outdoor Unit
  • (1) MSZ-GE12A Wall-mounted Indoor Unit
  • (1) PAC Simple MA Remote Controller
Product Category
Ductless Systems
Home Residence
Completion Date
October, 2010
Case Study Type
For Homeowners
Text Box Type
energy recovery systems/lossnay
energy savings/rebates/efficiency
passive house
retrofit/historic restoration

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