HUMIDITY IN THE HOME

YOUR HEALTH AND SAFETY

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 HUMID?

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 - YEAH!

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 your windows.

HOW DO I KNOW MY HOME'S HUMIDITY IS TOO HIGH?

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 walls.

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 including allergies.

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 maintenance problems.

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 ENERGY

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 boot.

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 HUMIDITY

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 not necessary.

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 direct heat.

IT'S HARD TO BE PATIENT

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 and healthy.

WHAT DO I DO NOW?

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 system.

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 “sweating”.  

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