Impact of Indoor Temperature Setting and Thermal Comfort on A Building’s Energy Consumption.
Buildings account for about 40% of global energy consumption and contribute over 30% of the world’s CO2 emissions. A large proportion of this energy is used for maintaining thermal comfort in buildings, but often outdated temperature settings are bigger energy hogs than they need to be. New technology offers real-time monitoring and the potential for significant energy savings.
Buildings account for about 40% of global energy consumption and contribute over 30% of the world’s CO2 emissions.
The indoor temperature of buildings is broadly relevant for many business decisions including building design, acting on efficiency incentives, and equipment specifications. Buildings are simulated in models to assess energy costs and savings potential, risk of moisture build-up, and cost-effectiveness of improvements in construction and energy codes. Many utilities base energy efficiency incentives, at least in part, on assumptions about thermostat set points and indoor temperature.
Air conditioner manufacturers, distributors, and installation technicians design, manufacture, and select equipment for new buildings, as well as replacement equipment for existing buildings, based on load calculations that critically rely on indoor temperature. When assessing the energy performance of heating, ventilating, and air conditioning (HVAC) systems, building insulation, and other devices such as heat pump water heaters, the heating and cooling set-points are typically the dominant factors driving energy consumption. In addition, the indoor temperature in any part of a building is not guaranteed to match the thermostat set-point-data, as temperatures can vary widely from floor to floor, room to room.
the heating and cooling set-points are typically the dominant factors driving energy consumption.
Despite their importance to our understanding of how buildings use energy, and for assessing opportunities to reduce building energy consumption, building set-points and indoor temperature are generally not well-studied or considered. Paying more attention to them is a smart business move.
For instance, higher indoor temperatures in summertime conditions would lead to less need to activate cooling systems because of more minimal cooling requirements. In situations where air conditioning is unavoidable, a wider range of acceptable indoor thermal environments would mean less cooling requirements and therefore less electricity consumption by air conditioning systems. Raising summer set-point temperature, without losing thermal comfort, has good energy-saving potential for all, as this strategy can be applied to both new and existing buildings.
Energy savings implications
According to the University of Southern California, simply setting a higher summer set-point temperature (SST) can bring up to 29% in energy saving. In addition, implementing a wider/varying range of indoor temperature for different times of the day and different outdoor conditions would help to reduce chilled water consumption by 34–40% and lower energy budgets for HVAC by 11%.
According to the University of Southern California, simply setting a higher summer set-point temperature can bring up to 29% in energy saving.
Table 1 shows a summary of some international case studies involving monitoring indoor temperature and thermal comfort. It shows that substantial energy savings could be achieved for both office and residential buildings, ranging from 6% reduction in HVAC electricity consumption in Australian office buildings by raising SST by 1°C, to 33.6% reduction in total energy cost in a hot desert area in Riyadh.
Reference: University of Southern California. Viterbi School of Engineering. Thermal comfort and building energy consumption implications
In a different way, through a graphic-analytical approach using an h-x diagram and statistical outdoor condition data, Riga Technical University found that by increasing the temperature of supply air by 2°C (from 19 to 21°C), then raising the indoor temperature, the energy consumption for cooling of outdoor air dropped by 7%.
Certain key functions in the performance of buildings should be taken into account when they need to meet carbon footprint and sustainability goals.
Control and monitoring of indoor temperature is one of those functions and it plays a crucial rule in improving the energy efficiency of a building. Understanding and modifying how your building performs on energy consumption and thermal comfort can eliminate waste of energy, improve occupant satisfaction, and achieve energy conservation goals.
The availability of new technology, such as LoRaWAN™ networks and wireless IoT (Internet of Things) sensors connected to the cloud, presents an opportunity for both new and existing properties to transform quickly into smart buildings with improved energy efficiency, sustainability, and data connectivity. The transition can be made effortlessly. No tools or additional IT resources are required for ‘out-of-the box’ installation of digi thermo sensors connected to our innovative cloud platform.
ANSI/ASHRAE 55-2017: Thermal Environmental Conditions for Human Occupancy
IEA (International Energy Agency). Buildings. Tracking Clean Energy Progress
University of Southern California. Viterbi School of Engineering. Thermal comfort and building energy consumption implications
Riga Technical University. Impact of indoor temperature on energy efficiency in office buildings
NREL (National Renewable Energy Laboratory). Residential Indoor Temperature Study