HUMIDITY IN THE HOME
YOUR HEALTH AND
Humidity is the amount of moisture in the air. It is in the
form of water vapor, a gaseous state. Humidity is a good thing
and we need a certain amount to feel comfortable. But in the
enclosed environment of a home, the wrong humidity level can
present problems for health or home maintenance.
To complicate things, simple activities can
dramatically change humidity levels. As a matter of fact, the
American Lung Association claims that the humidity in the home
average American home is above EPA acceptable recommendations
for indoor moisture. This provides a perfect environment for
mold spores and dust mites to grow.
HOW DOES MY HOME GET SO
First of all, every living thing requires and emits water
(even if Fluffy is "housebroken"). Your family; your pets; your
house plants; all add moisture to the indoor atmosphere as they
breathe and perspire. That decorative fountain and the flowers
you got for your birthday constantly introduce moisture into
the air. Did you know that the biggest contributers is
people breathing. The average human body gives off 2
liters of water during an 8 hour sleep period.
The construction of your home contributes to the moisture in
your home as well. Improper insulation and weather sealing,
along with features such as crawl spaces, if not properly
protected with a vapor retarder, can cause excessive moisture
in the air.
NO MORE COOKING AND CLEANING -
Another way we add moisture to our indoor environment is
through daily activities. Cooking, dish washing, doing laundry,
and showering contribute to moisture. Remember that fog you
wiped off of the bathroom mirror? That moisture had to go
somewhere. But no, this is not an except able excuse to stop
cooking and cleaning. Good try, though!
SO TELL ME, WHAT IS THE PERFECT HUMIDITY
FOR MY HOME?
Actually there is no one simple answer. It is all relative .
A general rule is between 20% and 40%.
To find the proper humidity level for you home, you must
take the outdoor temperature into account. As the temperature
outside decreases, your ideal indoor RH will also decrease.
Why? Since the difference between indoor temperature and
outdoor temperature is greater in the winter, and the warm
indoor air can hold so much more moisture than cold air, the
higher the indoor temperature and moisture content (RH), the
greater the risk condensation on the inside of your walls and
HOW DO I KNOW MY HOME'S HUMIDITY IS TOO
If your home starts feeling like a tropical rainforest and
rare orchids are suddenly growing out of your carpet, your
relative humidity may be a little high. Remember, condensation
can be a problem both in summer and in winter.
In summer, you may discover water dripping from toilet tanks
or condensation on water pipes. There may be condensation on
walls in cool areas, such as basements. Excess moisture in
these areas, in the form of condensation, presents an ideal
environment for the growth of mold and bacteria inside your
Musty smells and spores are living things you do not want to
nurture. Mold and mildew caused by excessive humidity can
exacerbate existing health problems and cause new ones
In the winter, excess moisture is frequently seen on
windows in the form of ice or fog-like cover. Excessive
moisture can cause peeling paint, rotting wood and other
HOW DO I KNOW MY
HOME'S HUMIDITY IS TOO LOW?
Too dry air causes discomfort in the form of parched skin
and lips, dry scratchy throat and nose, frequent respiratory
infections and other breathing problems.
If the air is too dry you may experience static electricity
“shocks” when you touch objects. Not only is this
uncomfortable, it can damage electronic devices. Even tiny
electrical discharges can make your computer (a very important
member of many households) very ill.
Fluctuating levels of humidity, which alternate between high
and low can be extremely harmful to fine wooden furniture and
art. This can cause cracking, warping and loosening of joints.
By the way, if you plan to make a move to an area with a
dramatically different climate, your precious furniture and art
may not adapt as well as you will.
I WANT TO SAVE
The recommendation to keep humidity levels at the low end of
the comfort spectrum during winter is intended to prevent
excessive moisture in the form of condensation. However, if
condensation is not a problem, that is to say there is only a
tiny amount visible on your windows, you’ll want to keep your
humidity at around 40% or maybe even 50% in the winter, because
the higher humidity can help you feel warmer. This means you
can turn the thermostat down a few degrees and save energy to
In the summer, the reverse applies. Lower humidity
reduces latent heat in your home, which will help you feel
cooler. A dehumidifier can make sure the air conditioner
doesn’t have to work as hard to make you feel comfortable.
Remember....It's not the heat, it's the humidity!
HOW CAN I MEASURE INDOOR
Towels that won't dry are a good measure of high humidity,
and getting shocked when you touch the cat is a pretty good
sign that the air is too dry. But if you have other uses for
your towels and pets, you can buy an inexpensive device called
a Hygrometer almost anywhere you find thermometers.
Hygrometers, like most devices, come in various price
ranges. The lower-priced devices are mechanical and sometimes
slower to respond than the digital, battery-operated versions,
which cost more. Also, expect some variation in accuracy. Once
I lined up 3 and found 3 different humidity levels reported for
the same spot at the same time. Most people use the hygrometer
as a general guide. Exact, finely calibrated readings are
Place your hygrometer where the humidity symptoms are most
obvious, in the room that you are most concerned about, or
where your family spends the most time. Never place it near a
heat source of any sort because that will skew the reading
(remember warm air can hold more moisture than cold air). Don’t
place your hygrometer near a radiator, a heat register,
chimney, or in any other location where it could be affected by
IT'S HARD TO BE
Hygrometers are slow to work their magic and produce
readings. It can take a couple of hours for your hygrometer to
adjust to a new location or to a sudden change in humidity.
Knowledge is power, and your hygrometer can help track your
home’s humidity and keep your family and your home safe
WHAT DO I DO
Now that you have determined your need for more or
less humidity you are ready to mitigate. First of all, try to
ensure that outside air stays out and inside air stays in by
having adequate weather-stripping, caulking, and insulation.
Oddly enough, super-insulated homes may suffer from excessive
moisture as well, because there is not enough ventilation. But
at least, this is a problem you can control by purposely
allowing air in.
You can use a humidifier to increase humidity. Humidifiers must
be used correctly in order to prevent mold growth in your home,
or even in the humidifier itself! They can be troublesome to
maintain. It is possible to purchase "whole-house" humidifiers
that must be professionally installed onto your heating/cooling
To decrease humidity you can purchase de-humidifiers, which
have tanks that must be regularly emptied. Once again, you must
be careful to avoid mold growth in the tank. Better to install
and use exhaust fans in kitchens, bathrooms, and laundry rooms.
Make certain that these vent to the outside. Installing vents
and attic fans is also recommended. You can buy insulating
tubing for cold water pipes to decrease
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