In addition to its focus on water conservation, the Watsonville Water Operations Center is designed to conserve energy while improving building performance and comfort. The ventilation and heating/cooling systems were de-coupled, resulting in a system that is much less energy intensive than a standard forced-air system. The building energy loads were reduced significantly by incorporating high-efficiency mechanical equipment. Likewise, occupancy sensors were included in the majority of spaces to reduce lighting loads. Natural ventilation, CO2 sensors in open areas, building chimneys, and roof-mounted solar panels further contribute to energy conservation, reducing fossil fuel use and greenhouse gas emissions while improving the overall building performance and occupant comfort. The building’s natural ventilation capability, use of natural light, and highly efficient building envelope will aid in the “passive survivability.”

The irrigation system is predominantly an efficient, automatically controlled drip system utilizing recycled non-potable water. All plantings have low water needs and all planting areas received mulch to maximize water retention, minimizing evaporation. Reclaimed water from the waste treatment facility will provide any required site landscape irrigation water during plant establishment.

Bioclimatic Design

The building, which is almost 290’ in length, is oriented on an east-west axis, allowing for the majority of the building’s program to be placed along the north and south facades. Solar heat gain is controlled through the building’s eaves and trees placed along the southern edge, and thermal mass is provided by a polished concrete radiant floor. The building’s tall section and open plan were designed to make the efficient program to feel generous and spacious. Skylights along the central corridor wash the white walls with sunlight and provide a connection to the outdoors to the interior.

The design was adapted in response to the site’s prevailing coastal Pacific winds to maximize comfort in the outdoor public spaces. Rooftop vent stakes along the building’s ridgeline allow these breezes to be harnessed passively, drawing warm air out of the interior naturally. Private offices are equipped with glass sidelights and operable clerestory windows to allow natural light and air to move through the building’s private and public spaces. This careful “opening up” of the building’s interior benefits the occupants as they work and engage with one another, furthering interaction and communication in an open, light-filled, and healthy indoor environment.

Annual Purchased Energy Use

Fuel Quantity Cost ($)
MMBtu kBtu/ft2 $/ft2
Electricity 126,00 kWh
$15,092.40 429 21..7 $0.76
Natural Gas
4,520 therms
$3,696.13 452 22.8 $0.19

Total Annual Building Energy Consumption

Fuel Cost MMBtu kBtu/ft2 $/ft2
Total Purchased
$18,788.53 881 44.5 $0.95
Grand Total
$18,788.53 881 44.5 $0.95

Annual End-Use Breakdown

End Use
Quantity MMBtu kBtu/ft2
Heating 415 MMBtu
415 21
Cooling 940 kWh
3.21 0.162
Lighting 27,200 kWh
92.6 4.68
Fans / Pumps
21,900 kWh
74.8 3.78
Plug Loads and Equipment
75,800 kWh
259 13.1
Vertical Transport
n/a n/a n/a
Domestic Hot Water
36.5 MMBtu
36.5 1.84
Other n/a n/a n/a

Data Sources & Reliability

Reliability - Energy simulations were performed using eQuest

Green Strategies

  • Solar Cooling Loads
    • Orient the building properly
    • Shade south windows with trees and shrubs
    • Shade building walls and roofs with trees
  • Daylighting for Energy Efficiency
    • Orient the floor plan on an east-west axis for best use of daylighting
    • Use skylights for daylighting
    • Use north/south roof monitors and/or clerestories for daylighting
  • Hot Water Loads
    • Use water-efficient faucets
  • Non-Solar Cooling Loads
    • Provide high-low openings to remove unwanted heat by stack ventilation
    • Use siting and topography to enhance summer breezes
    • Use operable windows
    • Make a high internal thermal mass building
  • Photovoltaics
    • Use a photovoltaic (PV) system to generate electricity on-site
  • Heating Systems
    • Use hot water heat distribution
  • Lighting Controls
    • Use occupancy sensors