How to justify an environmental room
The benefit of an environmental room is control of temperature, humidity, dirt and airflow.
Climate control helps you operate with consistent gun settings no matter what the external atmospheric conditions. Very low humidity can cause irregular charging and poor coverage. High humidity can cause the powder to clump and resist flow. Without a room to control the climate, the guns must be adjusted to compensate for changes in the temperature and humidity.
More consistent outcome, better process control, fewer rejects, less powder coatings waste, lower gun wear and less compressed air use. More consistency is the key. In climates with radical seasonal changes it is very helpful. In desert climates it is essential.