A building automation system (BAS) can be likened to the "brain" of a building which not only impacts indoor air quality, but also the financial profile of an institution where many resources are tied to the operation of its mechanical equipment. Because this single system influences so many assets, expenses, and aspects of a business, it is critical to manage it well.  At the Harvard School of Public Health, space conditions and indoor air quality are particularly important because they are closely tied to ongoing research and health studies in support of the School's mission and goals. HSPH undertook a broad upgrade of its building automation system in four of its buildings which included building upon Aircuity sensor systems and added controls from Siemens. This maximized the utilization of the system to ensure proper functioning, and the result saved significant amounts of money and energy for the School.


The price of energy powering its buildings costs the HSPH millions of dollars every year (about $3.5 million for Bldg #1 and #2 combined) which constitutes a large portion of the School's $6-7 million annual energy budget. Some of that energy use is unnecessary and could be optimized (for example, there are significantly fewer people using facilities from 7 am–7 pm on weekdays, and on weekends, meaning lights need not constantly be on during those times). The operation systems of buildings, ranging from lighting to HVAC, are central to those energy costs and could be upgraded and improved.


HSPH made a number of system improvements in four of its buildings, ranging from installing occupancy sensors for lighting and new electronic variable air volume (VAV) valve actuators, to upgrading pneumatic end devices controlling air systems to DDC. The results is a system that is far more energy efficient and saves hundreds of thousands of dollars in energy costs.

Key Statistics/Results:

  • More than $400,000 or approximately 25% in annual cost savings for two out of 4 buildings participating in the program. Awaiting savings data for the remaining 2 buildings.
  • Significant reduction in energy use for buildings involved in the program.

         Building #1: nearly 146,000 kWh in annual electricity savings
         Building #2: operating hours reduced from 8760 hrs./yr to 3640 hrs./yr which constitutes a nearly 60% reduction.
         Building #2: Emissions reduction amounts to 672.3 metric tons of carbon dioxide equivalent (MTCDE)

HSPH Building 1 Energy Savings

HSPH Building 2 Energy Savings

Lessons Learned:

Despite ongoing commissioning and retro-commissioning, opportunities for improvement still remain as HSPH seeks to map out all of the components, spaces, and needs of the system while continuing to identify new issues as they unfold. More controls and sensors will be added in the future to enhance the system's capacity to monitor and make adjustments as needed. Through careful monitoring and efforts to better understand these systems, the areas they serve, and building occupant needs, HSPH realized that its building operations could be significantly optimized through system upgrades. HSPH also learned the value of applying best practices to the operational side of business by upgrading to state-of-the-art systems and programming the BAS "brain" to run optimally and more efficiently. In sum, there is a large amount of energy and money to be saved in upgrading and automating building systems. Looking through these results is a necessary step of the process to justify the effort from the energy standpoint, and from the financial standpoint, it is important bear in mind future costs of renewal as technology continues to evolve. 


The Harvard School of Public Health upgraded the operation systems in four of its buildings. Siemens Building Technologies was also part of this effort.


Danny Beaudoin, dbeaudoi@hsph.harvard.edu

Additional Information:

 Vendor: Siemens Building Technologies