Measure Guideline: Supplemental Dehumidification in Warm-Humid Climates
This document covers a description of the need and applied solutions for supplemental dehumidification in warm-humid climates, especially for energy efficient homes where the sensible cooling load has been dramatically reduced. In older homes in warm-humid climates, cooling loads are typically high and cooling equipment runs a lot to cool the air. The cooling process also removes indoor moisture, reducing indoor relative humidity. However, at current residential code levels, and especially for above-code programs, sensible cooling loads have been so dramatically reduced that the cooling system does not run a lot to cool the air, resulting in much less moisture being removed. In these new homes, cooling equipment is off for much longer periods of time especially during spring/fall seasons, summer shoulder months, rainy periods, some summer nights, and some winter days. In warm-humid climates, those long off periods allow indoor humidity to become elevated due to internally generated moisture and ventilation air change. Elevated indoor relative humidity impacts comfort, indoor air quality, and building material durability. Industry is responding with supplemental dehumidification options, but that effort is really in its infancy regarding year-round humidity control in low-energy homes. Available supplemental humidity control options are discussed. Some options are less expensive but may not control indoor humidity as well as more expensive and comprehensive options. The best performing option is one that avoids overcooling and avoids adding unnecessary heat to the space by using waste heat from the cooling system to reheat the cooled and dehumidified air to room-neutral temperature.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy Building Technologies Office
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1160177
- Report Number(s):
- DOE/GO-102014-4502; KNDJ-0-40337-03
- Resource Relation:
- Related Information: Work performed by Building Science Consortium, Somerville, Massachusetts
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
RESIDENTIAL BUILDINGS
COOLING
DEHUMIDIFIERS
VENTILATION
HUMIDITY
HUMIDITY CONTROL
BUILDINGS
RESIDENTIAL
BSC
BUILDING AMERICA
DEHUMIDIFICATION
SUPPLEMENTAL DEHUMIDIFICATION
ENHANCED COOLING
CONDENSER REHEAT
SUB-COOLING REHEAT
DEHUMIDIFIER
HOT-HUMID
RELATIVE HUMIDITY
ELEVATED HUMIDITY
HUMIDITY SET POINT
MOISTURE GENERATION
Buildings