Fixing a problem with humidity or temperature
When it comes to humidity, a dehumidifier is the best way to solve the issue in a closed system.
If heat is the original problem in your grow room, you should make sure to cool it down before it turns into a health problem for your plants.
Adding ventilation is a good way to decrease the level of heat, as is placing an air conditioner into your grow room set up.
Another way of dealing with the problem is installing an air cooler before flowering. It evaporates water, therefore making the overall temperature of the room cooler. Make sure you don’t use it while the flowering stage is occurring, however, as it could make the level of moisture too high for your plants to be content.
To reduce excess heat, remove any equipment that produces heat and doesn’t need to be in the grow room. Some examples of this are large pumps or light ballasts.
Preventative measures are the best way to keep your grow room temperature from becoming a problem. You can get lights that are either air or water-cooled, therefore keeping the heat produced out of your grow room. It basically just uses tubing to redirect the heat produced by the lamps outside so the same amount of heat can be produced without actually affecting your grow room.