U.S. Air Force Staff Sgts. Will Davey and Chris Rundell, Heating Ventilation and Air Conditioning (HVAC) craftsmen assigned to the 633rd Civil Engineer Squadron, gain access to a maintenance room at Langley Air Force Base, Va., Jan. 5, 2016. Davey and Rendell fixed an HVAC system, ensuring personnel had heat to perform their mission in a comfortable environment. (U.S. Air Force by Staff Sgt. J.D. Strong II)

U.S. Air Force Staff Sgt. Chris Rundell, Heating Ventilation and Air Conditioning (HVAC) craftsman assigned to the 633rd Civil Engineer Squadron, analyzes an air flow controller system at Langley Air Force Base, Va., Jan. 5, 2016. As an HVAC craftsman, Rundell maintains electric, electronic and pneumatic controls in refrigeration and cooling equipment. (U.S. Air Force by Staff Sgt. J.D. Strong II)

U.S. Air Force Staff Sgt. Chris Rundell, Heating Ventilation and Air Conditioning (HVAC) craftsmen assigned to the 633rd Civil Engineer Squadron, removes a panel from an HVAC system at Langley Air Force Base, Va., Jan. 5, 2016. Rundell assisted with the completion of three different HVAC system work orders in the first half of his day. (U.S. Air Force by Staff Sgt. J.D. Strong II)

U.S Air Force Staff Sgt. Will Davey, Heating Ventilation and Air Conditioning (HVAC) craftsman assigned to the 633rd Civil Engineer Squadron, removes tools from his bag at Langley Air Force Base, Va., Jan. 5, 2016. Davey works with furnaces, boilers, stoves, heat exchangers, burners, blowers, fans and radiant heaters as an HVAC craftsman. (U.S. Air Force by Staff Sgt. J.D. Strong II)

U. S Air Force Staff Sgt. Chris Rundell, Heating Ventilation and Air Conditioning craftsman assigned to the 633rd Civil Engineer Squadron, grabs a crescent wrench at Langley Air Force Base, Va., Jan. 5, 2016. Rundell used the wrench to remove bolts from a boiler during an inspection. (U.S. Air Force by Staff Sgt. J.D. Strong II)

U.S. Air Force Staff Sgts. Will Davey and Chris Rundell, Heating Ventilation and Air Conditioning (HVAC) craftsmen assigned to the 633rd Civil Engineer Squadron, loosen bolts on an HVAC system at Langley Air Force Base, Va., Jan. 5, 2016. HVAC craftsmen install, maintain, repair and operate heating plants, systems and equipment. (U.S. Air Force by Staff Sgt. J.D. Strong II)