Source: November/December 2008 Althouse Cleaning Newsletter

Controlling Humidity, Airflow and Temperature to Correctly Dry a Home

When a home or business experiences water damage from a broken pipe, faulty appliance, water heater, leaking roof, etc. , the first priority is to quickly remove as much water as possible. Extracting water from the carpet with a truck mounted suction machine removes 90%. However if the last 10% of moister is not removed, mold will develop and cause secondary damage.  

Restoration professionals control drying by regulating humidity, airflow, and temperature (HAT).   The goal for the first 24 hours is to get the relative humidity below 40% Rh to prevent mold growth. 

Heat

Dehumidifiers draw in moist air, cool it to return the moisture to its liquid state, and pump the water to a drain or to the outside. Dry air is reheated and blown back into the room. Dehumidifiers work best at temperatures over 70 degrees, so heat is sometimes pumped into a building to achieve more efficient drying. 

Airflow

Air movers (blowers, axial fans, etc.) remove surface water and suspend it into the air. Water inside the material  then is drawn to the surface, which is then removed. 

Temperature

Furnaces can insure that refrigerant dehumidifiers can work efficiently at removing water vapor from the air. In buildings that have no heat, a mobile  furnace such as the Dri-eaz Dragon® can be used(sometimes a generator is also used if the electrical system was compromised by water damage).

Evaporation and dehumidification equipment creates a lot of heat as it runs. This is great for the winter, but it can cause problems during water damage restoration processes in hot climates like we experience in El Paso and Las Cruces. Therefore it's best to run refrigerated air conditioning from a home or portable unit when possible. Evaporative Coolers inhibit the drying process because they constantly add more humidity to the structure during their normal operation.