Another thing to remember is the humidity levels. During this period, dendrobiums do not need a lot of moisture. Very little water will be enough to keep their roots alive. Also keep in mind that their roots constantly need plenty of air circulation so you should place them where there is a lot of fresh air.
Remember, that is based on energy usage, not comfort-levels, which are the purpose of having an air conditioner, in my not-so-humble opinion. Fact: At night, the ideal temperature comfort range for Americans drops to 65 to 72 degrees Fahrenheit (or about 87 degrees if you are my wife).
Try and set your thermostat's temperature to the highest possible degree you can stand. The closer the temperature is on the thermostat to the temperature outside, the less your air conditioner has to work and the lower your energy bill will be. The ideal temperature for your thermostat setting is 78 degrees Fahrenheit. In the winter, it shouldn't be set above 68 degrees in order to maximize savings.