Project Title:

UFAD Field Study of Sacramento Capitol Area East End Complex

A detailed comparison of UFAD with conventional overhead systems in two high-performance office buildings.

Status (updated 7/18/2007): Continuing

Funding sources: Research Grants


Project Objective

Conduct a field study to compare the positive and negative impacts of underfloor vs. conventional air distribution in two new office buildings in the Capitol Area East End Complex in Sacramento.

Significance to Industry

Two new office buildings completed by the State of California designed with state-of-the-art "green building" design strategies provide a unique opportunity to compare the performance of UFAD and other design strategies with the performance of a similar building with an overhead HVAC system. The new UFAD facility, designated as Block 225, is a 330,000 ft2 6-story office building, with UFAD on the top 5 stories, and a conventional overhead system on the ground floor. A similar building, designated as Block 172, was built with a conventional overhead system on all floors. The parallel building program for these buildings provides a unique opportunity for comparative analysis.

Research Approach

We have developed an overall methodology that will include occupant satisfaction surveys of the occupants for both buildings before and after their move into the new buildings. The range of data to be collected in this field study will be derived from: (1) CBE's web-based occupant survey, (2) UFAD system design and operation specifications; (3) energy performance data; (4) monitoring of the physical environment using portable data-loggers and hand-held instruments; (5) cost data; and (6) productivity, absenteeism, and complaint log data. A comparison of pre- and post-occupancy survey results will quantify differences associated with moving from the original buildings into the new State office building for each group. The relative impacts on occupants of UFAD technology in comparison to conventional overhead systems will be assessed by comparing the magnitude of the above described changes as well as post-occupancy data between the two groups.

This is a long-range project, sponsored by the California Department of General Services (DGS), that will be conducted over a four-year period. The UFAD building Block 225 was completed and occupied during June and August of 2002. The first post-occupancy evaluation (POE) involved physical measurements and occupant surveys in January 2003 (winter mode) was followed by a second POE in August 2003 (summer mode). Secondary building recommissioning was completed on Block 225 in the summer and fall of 2005, and CBE will conduct the final POE and energy studies in 2006.

Media Files

Animation of East End Field Study, showing temperatures in a portion of the UFAD plenum. September 2002.

Click here for related publications>>

View of East End Buildings

Two recently completed State of California buildings provide a unique opportunity to compare UFAD and conventional HVAC systems.

View of East End Block 225 Building

The LEED-certified East End Block 225 building includes a UFAD system.

CBE sensors in underfloor plenum

CBE researchers installed temperature and pressure sensors in the underfloor plenum to study the system’s performance.