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).
The best air conditioning temperature for sleeping is whatever you can get by on with just a sheet over you. If you have the air conditioner set so low that you need pajamas and a comforter, you have it set too low. Try working your way up from that 82F to 84F, 86F, or even higher.