Air Purifiers

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Americans spend about 90 percent of their lives indoors. On average, indoor air is two to five times more polluted than outdoor air, due mainly to dust, pollen, mold, cleaner molecules and other contaminants. Air purifiers use filters to circulate your air and catch many of these extraneous particles, making the air cleaner and you less prone to irritation. Unlike humidifiers and dehumidifiers, which prevent mold, dust mites and other issues by controlling indoor humidity, air purifiers simply work as filters to collect extraneous dust particles that exist in the air.

Types of Air Purifiers

Room air purifiers are ideal for homes that don't have forced-air heating or cooling. They are also less expensive than whole-house models and usually weigh between 10 and 20 pounds, have a handle and stand on the floor or a table.

Dedicated ozone generators are a type of room air purifier. They produce large amounts of ozone, which reduce allergens such as dust, smoke, pollen, germs and mold but which also are likely to cause throat irritation and pose other possible health concerns.

Whole-house air cleaners are good choices if your home has forced-air heating. However, they can be expensive to buy and need to be professionally installed into the ductwork of your heating system. Most also need to be wired into your electrical system. They are also the best performing air purifiers, due mostly to high-efficiency filters.

Whole-house air filters are inexpensive alternatives to whole-house air cleaners are replace the existing furnace filter in a forced-air heating or cooling system. You slip out the old filter and slide in the replacement. They need to be replaced every one to three months.

Important Air Purifier Features

  • Fan: Most room air cleaners use a fan to suck in air through the filter. Those without a fan run more quietly, but they are usually less efficient. Look for models with a low-decibel fan.
  • Servicing indicator: To keep an air purifier working efficiently, you need to remove and wash the collector plate every month or so. This can be done in the sink, tub or dishwasher. An indicator light is available on many purifier models to conveniently remind you that the filter is due to be cleaned or replaced. This will help to keep you with the cleanest and most efficient air purifier quality.
  • Clean air delivery rate (CADR): Developed by the Association of Home Appliance Manufacturers, CADR measures how much clean air an air purifier delivers to a room in cubic feet per minute. Compare these rates on different models to gauge which will perform best.
  • Dust sensor and air-quality monitor: In some room models, dust sensors and air-quality monitors are available. They will raise or lower the fan speed automatically based on the surrounding air quality and dust levels. This may be convenient for people who use air purifiers when they're not at home or when they cannot monitor the air quality while it is running.
  • Ozone output: Ozone is a lung irritant, and is used in some air purifiers to chemically alter molecules in the air. However, it can actually exacerbate a breathing problem for air purifier users who inhale it. Relatively low amounts can cause chest pain, coughing, shortness of breath and throat irritation. For an air purifier that will work best for your breathing issues, you should choose one with little or no ozone output.

Air Purifier Cost

The initial cost of an air purifier unit varies extensively. While some basic models like whole-house air filters cost as little as $35, whole-house air cleaners can cost as much as $500. This depends on manufacturer, size, materials used in production and overall quality of the device.

Like all appliances, different air purifiers use different amounts of energy to operate. HEPA air purifiers usually use between 50 and 200 watts of energy. To put that into perspective, a typical lamp uses 60 watts, while a typical computer uses 365. While you will be using more energy, it will likely not cause too large an impact on your electric bill.

Air purifier maintenance is another storey. In order to keep your air purifier working properly, you need to replace filters regularly and on time. Some air purifiers have multiple filters, such as pre-filter, HEPA filter and carbon filter, all of which need to be replaced at different times. The typical HEPA air purifier filter should be replaced every three to five years, and it costs between $70 and $200 each. The pre-filter should be replaced every three months, and it costs between $20 and $30. The carbon filter should be replaced every six months, and it costs between $15 and $100. Still, the recommended times for filter changes can vary by model, so check your user manual before making any large changes.

Last Updated: January 18, 2012
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About Emelie Battaglia Emelie Battagila is a contributing writer for

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