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Heating, Ventilating & Air Conditioning (HVAC) systems, in general,
are designed to control interior temperature; however, they also have a major impact
on the ability to control moisture in or under a structure. While properly sized equipment may
offer limited interior humidity control, improperly sized equipment
may allow humidity to go unchecked, resulting in uncomfortable interior
conditions and fungal activity. HVAC systems and their associated
ductwork also directly affect conditions within a crawl space or under an
elevated house, where excessive moisture can invite termites and lead to
fungal activity and structural concerns. Owners are typically
unaware that the interior temperature they maintain also affects
conditions below the living space and that lower interior temperatures
require additional considerations.
Aside from pest and structural concerns, simply put, most homes and small
businesses in the Lowcountry are not capable of maintaining acceptable
indoor air quality*. Many have moisture-related problems unique to
the region and/or have deficient air conditioning systems; most, however,
were simply designed without regard to indoor air quality and do not
incorporate an HVAC System capable of providing the fresh air ventilation,
filtration and humidity control necessary for sensitive occupants.
If excessive moisture has been
discovered in or under your home or business; or if you
suffer from asthma or sensitivities to allergens or other irritants, Air
Plus
can help by providing you with a professional
HVAC evaluation. In
addition to adequate temperature control, the system will be evaluated for
humidity control, proper filtration and fresh air ventilation. If
deficiencies are discovered, Air Plus will make recommendations to adequately
address those deficiencies and facilitate project implementation.
NEW CONSTRUCTION
The
best time to address moisture and indoor air problems is before they
happen. A properly sized mechanical system may satisfy your
thermostat, but since moisture is only removed as a secondary function of
standard air conditioning, you may not feel comfortable due to elevated
humidity or humidity swings; and worse, elevated humidity may result in
interior mold and allow dust mites to flourish. A properly
designed mechanical system will not only satisfy the thermostat, it
will also provide effective humidity control, effective filtration and
provide fresh air ventilation for improved indoor air quality. Add
properly designed substructure (crawl space) moisture control and
issues such as sweating ducts, mold, cupping floors and substructure decay
will be eliminated (and termites hate a dry crawl space).
Residential structures are complex and the environment we live in demands
that all of these issues be addressed with new construction.
Unfortunately, building codes do not effectively address (if at all) these
issues and, without input from a design professional, mechanical
contractors have historically only addressed the "temperature" part of
indoor air quality.
Air Plus can help by providing you or
your contractor with a professional
HVAC load calculation and recommendations (scope of
work) for acceptable indoor air quality and interior & substructure
moisture control.
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 * ASHRAE (The American Society of Heating, Refrigerating, and
Air-Conditioning Engineers) defines acceptable indoor air quality as: air
toward which a substantial majority of occupants express no
dissatisfaction with respect to odor and sensory irritation and in which
there are not likely to be contaminants at concentrations that are known
to pose a health risk.
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PICTURES
FROM THE FIELD
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Location:
Merion Place,
Charleston National, Mt. Pleasant, SC
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The
owners of this 7-year old Charleston National home complained of a
"mold-like" odor in the Kitchen. Observations in the Kitchen and
Bathroom revealed a configuration prone to experience moisture
problems. The supply ducts in these two locations (located in the crawl
space) terminated at the subfloor and discharged
air into the "toe space" below the cabinets, which acts as a plenum. The
air is then discharged into the room via a vertically mounted air
register. The configuration allows for cold supply air (55-60 degrees) to
be trapped under the cabinets and blow directly onto
the adjacent floor, thereby cooling the subfloor to below the dew
point temperature of the air located in the crawl space, resulting in the
formation of condensation and subsequent fungal
activity.
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Location:
Jamaica Drive, Byrnes
Downs, Charleston, SC
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The
piece of furniture looks harmless enough, but the arrangement is trapping
cold air against the floor and causing condensation to form on the
subfooring. The wood is saturated and well above the 28% wood
moistrure content necessary to support active wood destroying fungus.
Fortunately, the situation was caught before major structural damage
occurred.
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Location:
Pignatelli Crescent, Dunes West, Mt. Pleasant, SC
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It
doesn't get much worse than this. The air handling unit located in
the crawl space of this home in Dunes West was literally sitting in the
mud. The floor insulation was falling down and the floor system was
beginning to rot. Mold-laden air from this unsanitary crawl space
was being readily drawn into the air conditioning system and distributed
throughout the home.
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Location:
Burningtree Road, Country Club II, James Island, SC
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In
addition to poor thermal performance and reduced energy efficiency,
improperly maintained or damaged ductwork or duct insulation can be
detrimental to your crawl space. With the insulation falling off,
the floor system above this section of ductwork is being cooled to below
the dew point temperature and condensation is forming on the joists and
floor insulation. The longer this goes undiscovered and/or
unaddressed, the more serious the problem will get. There is already
substantial fungal activity and structural damage will soon follow.
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