Managing indoor humidity in hot-humid climates is more important than ever for new, energy efficient homes equipped with whole-house mechanical ventilation. In these homes, air conditioning systems are less effective at removing humidity from the air, particularly during part-load conditions or shoulder seasons when cooling is normally not required (e.g., November-March). Yet, more humid outdoor air is brought into the house as a result of increased ventilation rates. Although tighter construction practices help reduce air infiltration, the net effect is an increased supply of humid outdoor air into the house.
These conditions tend to lead to increasing the risk for musty odors, mold-mildew, and comfort complaints (e.g., cold and clammy feeling). In addition, high indoor humidity can result in increased energy use because occupants tend to compensate by using a lower thermostat setting in the summer.
This TechNote provides an overview of strategies for improving humidity control in hot-humid climates (applicable as well in other humid climates). The focus is on supplemental dehumidification methods using commercially available equipment. Supplemental dehumidification is not intended to be used as a means for compensating for over-sized HVAC equipment or excessive building leakage rates.