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Controlling Moisture and Maintaining Proper Humidity Levels

Improving Your Home's Air Quality

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Controlling Moisture and Maintaining Proper Humidity Levels Photo © Mifflin

Keeping the correct humidity level in your home is important to your well-being, and while a little moisture can be beneficial, too much could be hazardous to your health.

Recommended Relative Humidity Level:

The recommended average relative humidity level is between 35% and 45%. This range will provide the best comfort for your family, while helping to protect your musical instruments, drywall, wooden furniture and other belongings or materials from the damaging effects of dryness or excessive moisture.

As relative humidity levels actually fluctuate depending on climate and air temperature, I've provided an average range to make it simpler to follow. How a home handles humidity depends on many factors including design, construction, vapor retarders and how airtight the building is. You can learn more about relative humidity by following the links provided below.

What Happens When Humidity is Too High?

When there is too much moisture in your home, moist air gets trapped in corners, basements and other closed areas. This is often very noticeable in bathrooms when moisture gathers in corners and creates mildew that is difficult to remove. Condensation can also accumulate in windows, causing water to drip down the window and wooden frames to rot. This moisture provides a perfect breeding ground for bacteria
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How to Remove Excess Humidity

What method you choose to remove moisture from the air depends on the severity of the problem, the season and where the dampness is. If it's winter and an area could benefit from heat such as a basement, heating that space could return it to a proper moisture level. However, if humidity is excessive you may need a combination of both heat and a dehumidifier to reach proper levels. A damp bathroom can benefit from an open window, or a ceiling exhaust fan to draw the moist air or shower/bath steam to the exterior of the home. In spring when heating is not an option, running a dehumidifier is your best option for removing dampness from the basement or main floor.
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Portable Multi-Function Units

When Should You Add Humidity?

During cold winters, your heating system can make the air in your home too dry, making it uncomfortable for you. It can also cause wooden items to crack. To improve the air quality, you can add a humidifier to those areas where you spend the most time, or you can install a whole house humidifier to your heating system.

In the summer when you are not heating, depending on the climate in your area, there may be too much moisture in your home, which can cause damaging mildew. To control this moisture, you need a dehumidifier, which removes unwanted humidity.
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How To Maintain an Optimum Humidity Level:

A hygrometer is a small instrument with a display that shows what the relative humidity level is in the room where it is located. Inexpensive and user-friendly, this little gadget can help you to monitor the air so you can adjust your humidity level when required, by either adding a humidifier or dehumidifier to your home.

Air conditioners also help in controlling moisture levels in your home, and some portable humidifiers are designed with adjustable built-in monitors that activate the unit when levels are too low, or turn it off when levels are too high.
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Size of Humidifier is Very Important:

If you need to add humidity to your home and you only have one portable humidifier, I would locate it in the bedroom to control the air where you spend the most time in a 24 hour period.

However, I must stress that the humidifier should be sized right for the room. Otherwise, you can be adding too much moisture. A humidifier with the adjustable humidity control as mentioned above, will help with moisture balance. Most humidifiers will denote on the packaging the recommended room size for the unit. Take a quick measurement of your room for this comparison.
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Humidifier Design Types

There are basically two design types of humidifiers - portable which includes small personal and room humidifiers, and whole-house units which includes console models and flow-through bypass humidifiers that can be professionally installed on the home's duct work to operate every time the heating system is working.
Definition of Humidifier
What a Whole-House Flow-Through ByPass Humidifier is
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Humidifier Care & Maintenance

Read your product manual and follow recommended guidelines for filter changes or cleaning. I cannot stress this enough - if your humidifier is running with a clogged dirty filter, you could be adding bacteria and mold spores to the room. Read my Humidifier Care & Mtce for tips to keep your unit operating efficiently.
Why Changing Filters is a Good Idea

Read More About Humidifiers & Dehumidifiers:

Air Quality Appliances
Humidifier Buying Tips
Dehumidifier Buying Tips
Difference Between Warm & Cool Mist Humidifiers
Whole House vs Portable Humidifiers
How to Buy a Home Humidifier - Video
Humidifiers FAQ
Step by Step Humidifier Wick Filter Replacement
Go to Main Humidifiers & Dehumidifiers Page
Go to Home Page

Other Helpful Online Resources:

Manage Your Moisture from ACCA Education Series
Air Psychrometrics by Engineering ToolBox
Winter Home Moisture Problems by Penn State
Dehumidifier Buying Advice by ConsumerReport.org
Indoor Molds by the University of Minnesota
Vapor Barrier - Wikipedia
Keep Your Home Healthy
Moisture Problems in the Home - Michigan State University

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