Designs That Work
Hot Humid Climate
Introduction
 A
hot-humid climate is defined as a region that receives more than 20 inches
of annual precipitation and where one or both of the following occur:
- A 67°F (19.5°C) or higher wet bulb temperature for 3,000 or more hours
during the warmest six consecutive months of the year; or
- A 73°F (23°C) or higher wet bulb temperature for 1,500 or more hours
during the warmest six consecutive months of the year.
The intense solar radiation in this climate imposes a large thermal load
on the house that can increase cooling costs and affect comfort. The
approach presented minimizes the impact of solar radiation on the building,
its mechanical system, and its occupants.
Moisture is a significant problem in this climate, more so in those areas
that receive more than 40 inches of annual precipitation. The ambient air
has significant levels of moisture most of the year. Since air conditioning
is installed in most new homes, cold surfaces are present on which
condensation can occur. Controlling the infiltration of this moisture-laden
air into the building enclosure and keeping moisture away from cold surfaces
are major goals of design and construction.
Housing types vary greatly throughout all of the different climate zones,
but nowhere is the contrast so great as in the Hot-Humid climate of the
southern United States.
In many parts of Florida, block wall assemblies predominate, whereas wood
frame is most commonly used in Texas. For this reason we have chosen three
different building profiles that we think best represent the Hot-Humid
climate:
- The “Houston” – two-story,
slab-on-grade, first floor brick veneer, second floor fiber cement lap
siding, conditioned attic with asphalt shingle roof.
- The “Maitland” – two-story,
slab-on-grade, both floors stucco, conditioned attic, tile roof.
- The “Orlando” – two-story, block stem wall
with slab, SIPS walls, Cement board siding/brick veneer, vented
unconditioned attic, metal roof.
- The “Montgomery” – one-story,
conditioned crawlspace, vinyl/aluminum lap siding, unconditioned attic,
standing seam metal roof.
 Additional information on construction methods and alternative
designs are included in the Builder's Guide Hot-Humid Climates at
Building
Science Press
and in the EEBA Water Management Guide at the
EEBA Bookstore.
1This definition is identical to the ASHRAE
definition of warm-humid climates and is very closely aligned with a region
where the monthly average outdoor temperature remains above 45°F (7°C)
throughout the year.
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