Product Brochure
9
Mixed-humid climates are defined as regions that receive more than 20 inches of annual precipitation, with
How much water will condense on the interior surface of the exterior sheathing (the first condensing surface) is
a function of the dew point temperature of the interior air, the amount of air leakage into the wall, and the vapor
permeability of the materials in the wall. Small amounts of condensation will not be a problem if the wall is allowed
to dry to the exterior.
Moisture is more of a significant problem in this climate than in areas that receive 20 inches or less of rain per year
in a single climate area. That’s because the ambient air in mixed-humid climates tends to have significant levels of
moisture most of the year. In addition, since air conditioning is installed in most new homes, cold surfaces are present
on which condensation can occur.
Since both heating and cooling occur for extended periods in mixed-humid climates, it can be difficult to determine
the correct method for moisture control. To add to the confusion, The American Society for Heating, Refrigeration and
that wall systems be allowed to dry toward the interior or exterior environment in mixed-humid climates and, if
possible, allow some drying in both directions.
The Building America Climate Regions
Mixed-Humid
Hot-Humid
Cold /
Moist (A)Dry (B)
Very Cold
Hot-Dry / Mixed-Dry
Marine (C)
MT
ID
UT
AZ
CO
NM
NV
OR
CA
W
WY
SD
MN WI
MI
IA
IL
IN
OH
PA
NY
NJ
MA
WV
KY
TN
GA
FL
SC
NC
VA
DE/MD
CT/RD
VT/NH
KS
OK
TX
MI
AR
LA
MS
AL
ND
NE
The Building America Climate Regions