Air Purifier Buying Guide

The first decision in choosing housewares is figuring out what your home needs. The options include air purifiers for cleaning, humidifiers for adding moisture to dry air, and dehumidifiers for controlling mildew in humid climates.

Air purifiers

Air purifiers are electronic air cleaners that capture allergens and contaminants, including dust, pollens, pet dander and odors. Place these appliances in heavily used areas of the home--air cleaners are perfect for Fido's favorite room. Unlike climate control appliances of the past, most of today's air purifiers are quiet and energy efficient. They clean the air as it circulates through an enclosed area, such as a room. Air purifiers will breathe a little fresh air into your home.

There are several cleaning methods available; most air cleaner systems use filters or electronic precipitators.

• Filtration systems: Filter-based air purifiers are the most popular among consumers. In this system, a fan pulls air through a paper or mesh filter. The filter can be a replaceable model or a permanent, washable model. Washable filters are good for trapping dust but do not trap pollen and smaller particulates. Many air purifier designs incorporate pre-filters that catch larger particles in the air flow to boost the efficiency of the main filter.


• HEPA filters: High Efficiency Particulate Arresting (HEPA) filters are designed to capture 99.97 percent of airborne particles measuring 0.3 micrometers or larger from the air as it passes through the filter. HEPA filters efficiently remove mold spores, bacteria and dust from the air that is filtered.


• Activated carbon: Filters are not efficient at eliminating odors; therefore, many air purifiers include some form of activated carbon in the design to absorb odors and chemicals.


• Electronic precipitators: The second most common type of air purifier, they draw air through an electrical field and use the electric charge to capture and trap particles on charged metal plates or filters. Some electronic precipitators use a fan to circulate more air at a time. These air cleaners release a small amount of ozone into the air; an important consideration if you use the unit in a small room.


• Ionizer purifiers: Both filtered cleaners and electronic precipitators can have built-in ionizing circuitry. Ionizers discharge electrons into the air, forming negative ions by attaching themselves to air molecules. The negative ions attract dust and pollen particles to form larger particles that are more easily trapped by filters. An ionizer helps the air purifier work more efficiently. However, the ionized particles may attach themselves to upholstery, drapes and carpets, increasing the need for vacuuming.

Humidifiers

Humidifiers provide year-round relief from the drying effects of low humidity climates, air conditioners and heaters. Furnaces and ACs moderate the temperature, but they also circulate a lot of dry air through the home. A humidifier evaporates water to send a fine mist into the room, providing soothing comfort for itchy skin and dry throats. Some humidifiers help regulate home temperature with warm steam or cool mist. There are several factors to consider when choosing a humidifier.

• Evaporative: An evaporative humidifier blows air over a wet wick to release moisture. The mist will be at room temperature or cooler and helps to cool a warm room. However, evaporative humidifiers can have noisy fans and the water is not sanitized while in the unit.


• Warm mist: A warm mist humidifier boils the water before releasing it as steam into the room. Boiling kills any germs and bacteria in the water before adding it to the air. Warm mist units are generally quieter than evaporative humidifiers, but they use more electricity. Also, they must be handled carefully during operation as the hot water and steam can cause injury.


• Humidistat: The humidistat displays the humidity level of the surrounding air. A home's humidity level should register below 55 percent. Higher humidity levels promote the growth of mold and mildew. Be sure your humidifier has a humidistat if you plan to use it regularly.


• Children: Humidifiers are used often to relieve stuffy heads and other cold symptoms in children. Models for children's rooms feature cute animal designs, extra quiet operation and an automatic shut-off function for safety. Warm mist humidifiers are comforting, but they contain hot water and should never be left in a child's room without adult supervision.

Dehumidifiers

Dehumidifiers are essential home appliances in humid climates. Allergy sufferers also benefit from home dehumidifiers. By removing moisture from the air, dehumidifiers restrict the growth of mold, mildew and dust mites, which thrive in humid air. Does your home need a dehumidifier? Check for the tell-tale signs; condensation on window panes, warped wood and peeling wallpaper are good indicators that a house needs a dehumidifier.

A dehumidifier removes moisture from the air by pulling the air into the unit, removing the excess moisture with collection coils and depositing the water into a bucket. The dehumidifier then pushes the drier air into the room. Air keeps circulating through the dehumidifier, making it less humid and more comfortable. Here are a few things to look for when purchasing a dehumidifier:

• Moisture removal: Removal is measured in pints per 24-hour period. Dehumidifiers come in different sizes to accommodate small rooms, large rooms and/or damp basements. Small, portable units may pull in 20 ounces a day while industrial dehumidifiers can pull in 50 gallons a day. The average home dehumidifier captures 10 to 30 pints of water in a 24-hour period. Humidity levels and the square footage of a home affect the efficiency of the dehumidifier. To view a chart of recommended sizes for the home check the table at the www.cooloff.org website.


• Humidity level: The optimal humidity level for a comfortable home environment is 30 to 50 percent. Many dehumidifiers will have a humidistat to monitor the humidity level and some can be set to shut down when the desired level is reached.


• Tank capacity: The collection tank of a dehumidifier must be emptied regularly. Be sure to check the tank capacity of a new unit to see how often it fills up.


• Automatic shut off: Turns the unit off when water has filled the tank to capacity, preventing an overflow. This is a good feature to have on a dehumidifier.

Air purifier care

Air purifiers help keep our homes healthy and comfortable. However, these convenient appliances can become breeding grounds for mold and bacteria. To keep an air purifier or humidifier clean, follow the manufacturer's maintenance instructions. Regular maintenence on these household appliances typically includes replacement of the filters, if the filters are not permanent. These air filters capture allergens and contaminants including dust, pollens, pet dander and odors. In general, HEPA filters should be replaced every two to four years, and smaller filters, such as pre-filters, should be replaced quarterly. Clean permanent home filters monthly. Collector plates usually slide out of the unit and can be rinsed off with clean water every month.

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