Humidifiers can make a home healthier and more comfortable. Maintaining the proper humidity levels in your home is important. When the temperature drops, the air is not able to hold as much water vapor and the humidity level drops. Low humidity levels can cause physical discomforts like dry nose, throat, lips, and skin. Since some bacteria and virus thrive in drier air, people are more likely to catch a cold in a drier environment. Indoor humidity levels should be between 30 to 50 percent, with about 45 percent being the ideal level. Raising the humidity levels is easy to do with the use of a humidifier. But with so many to choose from, how can you decide? In order to make a decision, it is important to understand the different types. The types can be categorized by the type of mist they produce, cool or warm.
Cool Mist Humidifiers
Cool mist humidifiers are either impeller, ultrasonic, or evaporative. Impeller humidifiers produce a cool mist using a high-speed rotating disk that breaks the water into fine droplets. The moist vapor floats up into the air and is dispersed at room temperature.
Ultrasonic humidifiers also produce a cool mist, but they use a metal diaphragm that produces ultrasonic sound vibrations instead of a fan. These are usually the quietest to run.
Evaporative humidifiers use a fan to blow air through a damp wick or filter. They are the most popular and usually produce the greatest amount of mist, up to 13 gallons a day. It is important to choose an evaporative humidifier with a tank housing and wick that are antibacterial.
Impeller and ultrasonic humidifiers use less electricity than other types of humidifiers. However, the Environmental Protection Agency (EPA) and the Consumer Product Safety Commission (CPSC) have shown that ultrasonic and impeller humidifiers can raise the level of airborne particles in the home beyond acceptable levels, especially if tap water is used. Minerals in tap water can cause a crust deposit, or scale, to form in the humidifiers that are breeding grounds for microorganisms.
As the humidifiers are used, microorganisms and minerals are dispersed into the air, which can cause a white dust to appear on surfaces. To combat this problem, you can use distilled water, although many brands now have filters that reduce this problem. Evaporative filters do not appear to raise the level of mineral levels in the air, although they were not tested by the EPA. Demineralization cartridges, cassettes, or filters might also be available for use with your humidifier. However, their ability to remove minerals has never been tested to see exactly how well or for how long these devices work. If a white dust begins to appear on surfaces, the minerals are no longer being removed. Bacteriostatic chemicals are also available that will prevent microorganism growth.
TIP: Our HVAC/plumbing consultant Wayne McCarthy adds, “Installing a good quality filter on your faucet, or reverse osmosis unit, should remove most impurities from your water. This will also provide you with better drinking water.”
Warm Mist Humidifiers
Warm mist humidifiers create steam by heating the water. They are also known as steam vaporizers. They are usually a little more expensive to buy and use more electricity than the other types of vaporizers. However, they do not disperse minerals into the air like ultrasonic and cold mist humidifiers. Also, because the water is heated, it kills most microorganisms that would otherwise be dispersed. Care must be taken when using these around children or pets.
Choosing the Right Humidifier
When looking at humidifiers, factor in all the costs. Impeller and ultrasonic vaporizers might be less expensive initially, but the cost of using distilled water or demineralization cartridges and filters could make them less cost effective in the long run. Evaporative filters have wicks that need to be replaced which can also run the cost up. Warm mist humidifiers use more electricity to run.
Ultimately, choosing may come down to personal preference. No matter which type of humidifier you decide to buy, size should be considered. For a 4 to 5 room house, a humidifier needs to output about 2 to 3 gallons of water a day. Make sure that it will be easy to fill. Some models come with a filler hose that allow it to connect to a faucet. Others might be able to be filled using a bucket or jug. If the humidifier comes with tanks, make sure they will not be too big to fit under a faucet or too heavy when full for you to carry.
It is best to purchase a humidifier that has adjustable fan speeds. Finding one that has a built in humidistat and an automatic shutoff is also a good idea. Some brands will automatically turn off when humidity levels reach a certain level. This ensures that your home doesn't get too humid, which can also cause health problems.
Using Your Humidifier
Using a humidifier incorrectly can be more damaging than not using one at all. Always follow the manufacturer's guidelines, and contact your physician if you develop respiratory symptoms that might be associated with using your humidifier. Humidifiers should be placed at least 6 inches away from an inside wall. Since warm, moist air rises, it is better to place the humidifier on the ground floor.
Use a hygrometer to monitor the humidity levels in your home. If water begins to condense on windows, or the area around the humidifier becomes damp, either relocate the humidifier or reduce its use. It is very important that all humidifiers are cleaned frequently when in use--at least every third day. Empty the tank and use a brush to clean it. Remove any scale, deposits, or film that has formed on the interior surfaces and wipe them dry. Always unplug the unit before cleaning. The manufacturer's suggestions on the use of cleaning products or disinfectants should be followed. If they do not provide them, clean surfaces with water and a 3 percent solution of hydrogen peroxide. Whenever the humidifier is not being used, its tank should be emptied and wiped dry. Throw out any used demineralization cartridges, cassettes, or filters, and store the unit in a dry location. When it is time to use the humidifier again, clean the unit thoroughly first.
Looking to purchase a new humidifier? Check out our Humidifiers Buyer's Guide.
Wayne McCarthy, plumbing and HVAC professional contributed to this article.