A 2009 report shows that widespread misunderstanding about where to measure the air temperature in data centers is leading to significant energy waste. Data center operation guidelines from ASHRAE (the American Society of Heating, Refrigerating, and Air-Conditioning Engineers) recommend operating at temperatures just under 27° Celsius (C), which is 80.6° Fahrenheit (F). However, this level refers to the temperature taken at the server air inlet, not at the hot or cold aisle or the computer room air handler (CRAH).