Level 3 Energy Audit

Architect of the Capitol U.S. Capitol Building | Washington, DC



31 recommended ECM and O&M projects for the U.S. Capitol Building were developed through the process of a Level 3 Energy Audit, where the building energy usage was compared to metered energy data in a complete energy model. Estimated cost to implement the recommended projects was $10.5 million with an associated savings of $3.2 million annually. Two-thirds of the construction cost and annual savings were attributed to the building-wide replacement of the pneumatic HVAC controls with Direct Digital Controls (DDC), which includes replacing the controls on air handling units, reheat coils, and space (zone) temperature sensors. High energy use in the building was correlated to the older controls that created a large degree of simultaneous heating and cooling. Significant HVAC system energy savings opportunities were also associated with resetting cooling coil discharge temperatures to minimize reheat energy use and improve control of exhaust fans.

Of the 31 recommended ECMs, many also involved lighting retrofits and controls. Approximately 50% of the lighting savings were realized from the conversion of inefficient lighting, such as incandescent, to more efficient lighting, such as LED. Another 40% of the lighting savings were associated with the use of occupancy sensors that turn lighting fixtures off when not needed. The remaining lighting savings come from reducing the wattage in over-illuminated spaces with more efficient fluorescent lamps and ballasts.

recommended ECMs & O&M
  • Exterior Incandescent Lighting Pendants to CFL
  • Incandescent Lamps to CFL Lamps (Sconces)
  • Occupancy Sensors Installation in Conference Rooms
  • Incandescent Lamps to CFL Lamps (Chandeliers)
  • Incandescent Flame Bulbs to CFL (Chandeliers)
  • MR-16 Incandescent Spots Convert to LED
  • Incandescent Flame Bulbs to CFL (Sconces)
  • Table Lamp Replacement - Incandescent to CFL
  • Incandescent Spots Convert to LED Spots
  • Burmidi Incandescent Hallway Lighting to LED Spots
  • Occupancy Sensors Installation in Offices
  • Dome Mural Lighting Replacement
  • Interior Dome Gallery Level Lighting Replacement
  • T8 Lamp Wattage Reduction
  • Occupancy Sensors Installation in Corridors, Rest Rooms
  • Occupancy Sensors Installation in Kitchens
  • Exit Sign Replacement - Fluorescent to LED
  • T12 Lamps & Ballasts Convert to T8
  • T8 Lamp & Ballast Replacement
  • Condensate Pump Leak Repairs
  • Cooling Coil Discharge Temperature Reset
  • Exhaust Fan Controls
  • Full Pneumatic Control Replacement with DDC Kitchen Exhaust Hood Control
  • Premium Efficiency Motor Conversions
  • Chimney Exhaust Fans - De-energize in Summer
  • Water Meter Installation
  • Low Flow Plumbing Fixtures/Faucets
Recommended O&M
  • Carry-out Coolers - De-energize during recesses
  • Steam Kettle Deactivation
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$3.2M annual savings

31 energy projects