Aprilaire 700M Reference Manual page 6

THESE BENEFITS CAN BE GROUPED INTO
FOUR GENERAL CLASSIFICATIONS:
• Comfort
• Health
• Preservation
• Energy Conservation
Comfort
Did you ever step out of your shower in the morning and
notice how warm it is in the bathroom? It is actually
muggy. It is probably about 75°F, and the RH may be 60-
70% because of the water vapor being added to the air
while showering. If the phone rings and you have to step
out into the hall to answer it, what happens? You feel
chilly! Yet the temperature there is probably about 70°F.
Just 5°F cooler than in the bathroom, yet you are shivering.
Why? Because you just became an evaporative cooler.
The air in the hall is dry; and the RH can be as low as
up to 75°F and more in order to feel warm, and even then,
it feels drafty and chilly because the evaporative cooling
process is occurring. Proper RH levels make you feel
more comfortable at lower thermostat settings.
This cold effect is not the only discomfort caused by too-
dry air. Static electricity is another indication of low
humidity levels and a condition that's consistently annoying.
Proper RH will reduce this discomfort. And optimum RH
levels can now be achieved without constant manual
adjustment of the humidifier control device, using the
newest generation of Aprilaire automatic humidifiers.
Health
Proper RH is helpful for relieving problems aggravated by
air that is too dry.
* 1. Department of Microbiology, Mount Sinai School of Medicine article, Influenza Virus Transmission Is Dependent on Relative Humidity and Temperature; 2007; New York, New York, United States of America
http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.0030151
2. Oregon State University College of Oceanic and Atmospheric Sciences www.pnas.org/cgi/doi/10.1073/pnas.0806852106
10-15%. You are wet, and
this thirsty air goes to work
on your skin. It evaporates
the water, and as it does,
your skin is cooled. This
same type of thing goes on
day after day, every winter,
in millions of homes. People
are turning their thermostats
Low humidity can make you
more susceptible to catching
a cold or flu viruses. How? Air
that is too dry dries out your
nasal membranes and makes
the lining of your nose more
susceptible to bleeding and
infections. Also, low levels of
humidity have been linked to
the speedier progression and transmission of viruses
in the air*. Whole-house humidifiers equipped with
automatic control can maintain a proper level of humidity
for a healthier and more comfortable environment.
What do doctors say about humidity? Ear, nose, and throat
specialist, Dr. Arthur W. Proetz, is quoted in the Annals of
Otology, Rhinology and Laryngology:
"In the struggle between the nose and the machinery in
the basement, sometimes the heater wins and sometimes
the cooler, but seldom the nose. The nasal mucus contains
some 95% of water. To begin with, it is more viscous than
mucus elsewhere in the body and even slight drying
increases the viscosity enough to interfere with the work
of the cilia. Demands on the nasal glands are great even
under usual conditions, and they cannot cope with
extreme dryness.
"Experience has shown that with winter approaching, the
first wave of dry-nose patients appears in the office when
the RH indoors falls to 25%. It would seem, therefore, that
35% would be regarded as a passing grade but 40% as
something to shoot for.
Preservation
The addition or reduction of moisture drastically affects
the qualities, dimensions, and weights of many materials.
For example, wood, leather, paper, and cloth all contain
water. Not a fixed amount of water, but an amount that
will vary greatly with the RH level of the surrounding air.
Take, for example, a cubic foot of wood. At 60% RH,
the wood will hold over 3 pints of water. Now, if the RH is
lowered to 10%, the water held by the wood will not fill
even one pint bottle. So we have, in effect, withdrawn 2
½ pints of water from the wood by lowering the RH from
60% to 10%.