For preservation purposes, cooler temperatures are always recommended. The temperature of the display space should not exceed 72 °F. A lower temperature of down to 50 °F can be considered safe for a majority of objects. The maximum acceptable variation in this range is 5 °F, meaning that the temperature should not go above 77 °F and below 45 °F. As temperature and relative humidity are interdependent, temperature should be reasonably constant so that relative humidity can be maintained as well. Controlling the environment with 24-hour air conditioning and dehumidification is the most effective way of protecting an exhibition from serious fluctuations.