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).
However, if your first priority is remaining comfortable, you might want to set the temperature lower, even though doing so is more expensive. When it comes to energy usage and wear on the air conditioning system, the warmer you keep your home, the better. Set the thermostat to 78 degrees Fahrenheit, which is the Energy Star recommendation for the coolest you should keep your home.