An Introduction to Thermostat Setbacks

Commercial buildings represent a significant sector of overall energy consumption, necessitating the implementation of effective energy management strategies. Maintaining optimal occupant comfort while minimizing operational costs is a key goal for all facility managers and building operators. Achieving energy savings through the strategic application of thermostat setbacks is an established method to support these goals.

Fundamentals of Thermostat Setbacks

Thermostat setbacks are the practice of adjusting the temperature setpoint of a building’s heating, ventilation, and air conditioning (HVAC) system differently during periods of occupancy and no occupancy. Implementing a setback (reduce the target temperature) reduces the building’s energy demand when it is not occupied. The underlying principle is analogous to turning off the lights when a room is not occupied.

What Are Thermostat Setbacks?

By allowing the building temperature to deviate within a wider range while a building is unoccupied, the HVAC system operates less frequently and for shorter durations. This decreased operational demand directly translates to lower energy consumption and consequently, reduced utility costs. 

Studies Show Setbacks of 7°F to 10°F Degrees Reduce Energy Usage

Research conducted by the U.S. Department of Energy (DOE) and various industry studies show a direct correlation between thermostat setback implementation and reduced energy consumption. Specifically, adjusting the thermostat by 7°F to 10°F degrees Fahrenheit for a duration of eight hours daily can yield energy savings of up to 10% on heating and cooling expenditures[1, 2]. For example, a facility manager could create a setback from 7 PM to 7 AM, when the building is unoccupied, and still leave enough time to fully condition the space before occupants arrive in the morning. Depending on the occupancy patterns the setbacks can be even more aggressive reaching 10 or 12 hours. Another DOE study found that aligning HVAC operation times with business hours can result in an additional 6% reduction in energy usage[3]. The benefit of these strategies is cumulative and can result in a 16% reduction of energy usage. For facilities that are unoccupied for extended periods, such as overnight or weekend closures, the achievable energy savings can exceed 20%[4].

Beyond the Basics: Smart Strategies

While achieving savings through basic setback strategies based on a building’s occupancy schedule is relatively straightforward, given a building’s occupancy schedule. To truly optimize energy use, you look for the perfect thermostat setback. As time passes and your building management system gathers data about your building using AI tools can help identify the balancing point between savings and comfort. However, until the data is available applying simple logic based on a building’s occupancy schedule will provide significant energy savings. Some of the ideas to create and implement more advanced setbacks will be determined on an individual building level. They include:

• Time-of-Use (TOU) Rates: When utility companies offer time-of-use pricing, setbacks can be scheduled during peak demand periods, when electricity is most expensive.
• Occupancy Sensors: These devices can be used in combination with smart thermostats to adjust the temperature based on whether a room or building is occupied.
• Zone Control Systems: In buildings with multiple zones or buildings with RTUs that support specific zones, setbacks can be created independently for each zone or RTU.
• Data-Driven Adjustments: Using data about your building’s historical temperatures, HVAC performance, and occupancy patterns can help you fine-tune your setback schedules for maximum efficiency.

Addressing Common Challenges

Managing thermostat setbacks across multiple zones and accommodating variable occupancy schedules present operational challenges. Advanced building management systems offer solutions to these complexities through features such as centralized scheduling, override management with automated reversion, and data-driven decision-making capabilities.

Conclusion

The strategic implementation of thermostat setbacks presents a tangible and effective method for reducing energy consumption and associated costs in all buildings. The magnitude of savings will depend on a building’s occupancy schedule and relevant building sensors. A 7°F to 10°F degree adjustment during those periods without occupants can result in a 20% or more reduction in HVAC energy usage. Advanced implementation strategies, including leveraging time-of-use electricity rates, employing zoned thermal management, and utilizing data-driven insights to refine setback parameters, can further enhance these energy efficiencies. By embracing well-informed thermostat setback strategies and leveraging available technologies, commercial building owners and operators can realize substantial energy and cost savings while contributing to broader sustainability objectives.

This is the first in a series of blogs designed to inform contractors and building owners on the benefits of using thermostat setbacks and provide a guide on how they can be easily implemented. Contact us to learn more about using UBX in your building.

References:
[1] U.S. Department of Energy. Programmable Thermostats. https://www.energy.gov/energysaver/programmable-thermostats

[2] Trane®. Setback Thermostat: Energy-Saving Solution. https://www.trane.com/residential/en/resources/glossary/setback-thermostat/

[3] Powerley. Myth Buster: Can a Thermostat Setback Save on AC Costs?. https://powerley.com/setback/

[4] Minnesota Center for Energy and Environment (MCEE). Thermostat setpoints have big impacts on heating bills for businesses. https://www.mncee.org/thermostat-setpoints-have-big-impacts-heating-bills-businesses