Heat from data centres can raise temperatures in downwind localities by 2.2 degrees Celsius: Study
The waste heat generated by a single data center could exceed the amount emitted by 40,000 U.S. households, according to lead author David Sailor, professor and director of the school of geographic sciences and urban planning at Arizona State University.
Arrays of air-cooled condensers that condense turbine exhaust steam can exhaust air heated to 14-25 degrees Fahrenheit (about 8-14 degrees Celsius) above the surrounding air temperature, creating thermal plumes that move downwind over adjacent areas, the researchers said.
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“These are such a heavy load of electricity consumption and therefore heat emissions that we started to worry about the impacts they could have locally but also in downwind neighborhoods,” Sailor said.
“As we do more measurements under different atmospheric conditions, I think we will see more significant impacts around data centers,” Sailor said.
While previous studies have used remote sensing data from satellites to historically estimate the heat impact of data centers, the study published in the Journal of Engineering for Sustainable Buildings and Cities is the first to directly measure air temperatures upwind and downwind of data centers to record the real-time effects of waste heat on surrounding communities, the researchers said. In June, the team installed highly accurate, fast-response temperature sensors that record data in cars driving around Phoenix-area data centers and nearby neighborhoods. 18-25 October 2025.
Using multiple cars allowed the researchers to simultaneously measure upwind and downwind temperatures of four selected facilities, from a 36-megawatt single-building data center in Mesa to a 169-megawatt colocation campus in Chandler (both cities in Arizona).
The team said the chosen centers reflect the typical design of “hyperscalers” that house thousands of servers and use primarily air-based cooling systems.
“Five migrations at four sites in the Phoenix, Arizona metropolitan area, ranging from a 36 MW (megawatt) single building data center in Mesa to a 169 MW colocation campus in Chandler, reveal that downwind air temperatures increased by as much as 2.2 degrees Celsius, and average downwind air temperatures were 0.7 to 0.9 degrees warmer than upwind areas,” the authors wrote.
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“Thermal signatures were detected at distances of up to 500 m (meters) from the perimeter of the facility,” they said.
Contributing an additional heat island size of one or two degrees could significantly impact lives, especially in places where extreme heat already poses public health risks, Sailor said.
For example, a one degree increase in air temperature is enough to increase the use of air conditioning in all neighborhoods. The lead author said these air conditioners emit even more heat into the environment.
