Fetzer Winery Administration Building
Sustainability - Interior Lighting

"We designed the roof and clerestory windows to get as much natural light as possible across the full depth of the building. We built a physical model that was then studied at PG&E's research center down in San Francisco."
— Tom Faherty, Valley Architects

The Heliostat physical simulator at PG&E's Pacific Energy Center (PEC) in San Francisco was used with the physical building model to optimize daylighting design, including clerestory light scoop size and shape and louvering.

In addition to the high proportion of daylighting, a general approach of low ambient light levels with lots of user-controlled task lighting minimizes overall lighting energy usage.

Even given the high level of care and attention given to daylighting, the overall provision of electric lighting for ambient levels was determined conventionally, with controls provided so that lighting would only be used as required in operation. For assurance in sizing HVAC systems for thermal comfort, heat loads from lighting were similarly calculated based on conventional usage, again providing for generous capacity that would only be used as needed.

Control systems monitor and provide for adjustment of both daylighting and artificial lighting.

There were concerns about the engineering uncertainty of sizing window apertures to achieve daylighting effectiveness without too much heat input. In the actual building, the daylighting apertures are probably somewhat undersized, since the design studies assumed white walls, while the actual walls are a less-reflective earth color.