General recommendations suggest that you should not go below 10°C (50°F) or above 28°C (82°F). Although this seems a wide range these are the extremes and it is far more common to keep the ambient temperature around 20-21°C (68-71°F)...nudging the thermostat higher may also leave less time to recover from a cooling failure, and is only appropriate for companies with a strong understanding of the cooling conditions in their facility. Recommendations on server room temperature vary greatly.