The recommended temperature range for server racks is typically between 68 to 77 degrees Fahrenheit (20 to 25 degrees Celsius). Many modern servers are perfectly happy with 45 degree celcius operating temperature. USV's have to go out theough - battteries do not like that. This guide says that:. Modern equipment can run quite hot, even close to 30 degrees, so you can run hotter, but the hotter you run the less headroom you have for: aircon being off, say for servicing, or failure. Maintaining 68°Fā77°F (20°Cā25°C) minimizes overheating risks while balancing cooling expenses.