In the world of restorative drying there are three primary types of equipment used to create a building atmosphere that enhances evaporation: refrigerant dehumidifiers, desiccant dehumidifiers, and heat systems. For jobs beyond just a few rooms contactors have two primary options – desiccant dehumidifiers and heat systems. As to which is better, that depends upon the circumstances. In general, an open system that replaces building’s moist air with heated fresh air will speed drying more than closed systems that pull moisture out of the building’s air. But not all
Heat systems perform best when ambient dew point temperatures are low to moderate lower and the building can be heated to a temperature between 90 -110° F+. The heat will warm the materials and greatly accelerate the evaporation process. Because heat systems replace the building’s air with hot fresh outside air rather than actually drying the air, the building air humidity levels drop rapidly, the drying process begins sooner, and the air quality is better.
Heat is extremely effective at drying dense materials such as earth, cement, wood, and drywall. When ambient temperatures are cool to cold and no heat is available for the water damaged structure, heat is the only way to dry.
Heat systems are less effective when ambient conditions are hot and humid and upper drying temperatures is restricted. Heat can also be an issue when buildings are occupied.
Desiccant systems work best when ambient temperatures are relatively high or the building has an operational heating system. Because they are a closed system and do not utilize outside air, they can achieve low relative humidity levels even when the outside dew point is high. In addition to drying the air, some of the heat that dries the desiccant wheel gets transferred to and raises the temperature of the building air. The combination of low relative humidity and warmed air make desiccants an effective drying tool in many cases. Desiccant systems are not suitable for drying out dense materials in cool or cold conditions. The process of extracting moisture from the air is energy intensive. Under most circumstance, desiccant drying is slower than heat drying as there is less energy available for the evaporation process.