Grantee Question:
A grantee from Florida asks: Our city is preparing a policy for setting A/C and heating temperatures in City-owned facilities. This policy will say, “A/C occupied temperatures shall not be less than 78 °F and heating not more than 68 °F. A/C unoccupied temperatures shall not be less than 82 °F and heating not more than 60 °F.” Do you know of any standards that we can reference for our policy, or other grantees that have similar policies? 

TAP team responds:
The control of seasonal temperature settings for heating, ventilation, and air conditioning (HVAC) systems is a simple measure that can bring significant energy savings to municipalities. HVAC equipment that can be shut off during unoccupied hours should be shut off promptly, after hours, just before the end of the workday, and over weekends and holidays. In addition, modifying the temperature setting range during the workday can significantly reduce a building’s energy consumption. A temperature setting policy for HVAC systems ensures that all facilities within a municipal government achieve greater energy efficiency and conservation by maintaining building temperature and having ventilation fans run only when needed.

HVAC control systems reduce both temperature and ventilation based on the occupancy schedule in the building. For occupied spaces, Federal guidelines call for the following thermostat set-points:

Heating set-point = 68 °F
Cooling set-point = 78 °F

The City of Atlanta’s energy manager emphasizes the importance of unoccupied set-points: “My opinion is that the unoccupied-period set-points are more important in that they provide the greatest opportunities for conservation when no one is even in the building.” 

Individual Federal agencies have agency specific recommendations and it should be stated that energy conservation measures should not have a detrimental effect on interior thermal comfort or indoor air quality. Since evaporation rates decline as humidity levels increase, the set-points for cooling in humid climates might need to be lower than 78 °F. The American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) Standard 55 - 2004 "Thermal Environmental Conditions for Human Occupancy" recommends temperature ranges that have been found to meet the needs of at least 80% of individuals. The following table outlines these ranges:

A municipality’s thermostat set-point policy should be developed in conjunction with an implementation plan that specifies roles and responsibilities to carry out and monitor the implementation of the policy. The plan should address how department directors designate positions responsible for implementing energy conservation standards at each facility within their department. In cases where a facility is utilized over multiple shifts, someone should be designated for each shift. The current list of names by facility should be maintained and provided to the “Municipal Energy Team” via their department representative. In addition to the facility manager, every building occupant should be informed and empowered to be an energy saver and member of the energy team responsible for carrying out the policy.

Once the roles and responsibilities are established and clear, the air conditioning and heating control policy can be rolled out. Here is an example of a Temperature policy developed by the City of Atlanta:

Atlanta's Temperature Policy.pdf (114.33 kb)

Has your state, city, county or tribe implemented a policy mandating temperature set-points? How successful was the policy and what were some of the lessons learned as it was rolled out and enforced across your municipality’s portfolio of facilities?  Please, share your questions, lessons learned or post your sample policy in the comments section below.

Sources:

ANSI/ASHRAE Standard 55-2004, Thermal Environmental Conditions for Human Occupancy, http://www.ashrae.org/pressroom/detail/13394  http://www.ashrae.org/pressroom/detail/13394

Federal Energy Management Program's (FEMP'S) Operations and Maintenance Best Practices Guide, August 2010,  http://www1.eere.energy.gov/femp/pdfs/omguide_complete.pdf

Content for this blog post courtesy of Mitch Brown, Southeast 2 Regional Coordinator, ICF International.