In the drying of gases the higher the temperature, the more moisture the gas will hold. This may result in a dryer much larger and more expensive than need be if the temperatures were held to the lowest practical level. Likewise, if the desired effluent moisture content is specified lower than is actually required, excess quantities of desiccants or special desiccant may be required to obtain requested results. The resulting equipment may be larger and/or more expensive than necessary.

If the gas contains entrained water, the use of a separator prior to the coalescer filter should be employed to reduce the size of the drying equipment and also to prevent the possibility of desiccant breakdown.