Furnace Filters
Furnace Filter Tips On How To Keep Your Furnace Pushing Clean Air

Furnace Filter Tips On How To Keep Your Furnace Pushing Clean Air

Have you ever noticed that no matter how much you clean, you can still see particles floating in a beam of sunlight coming in through a window?

This isn't just dust! It's made up of pollen, plant and mold spores, pet dander, lint, bacteria and other contaminants. Regular daily activities within the home, such as dusting, vacuuming, cooking and smoking, can increase particulate concentrations. And major home remodeling and renovation projects can introduce even higher levels of particles in the home!

These particles, measured in microns, range in size from fairly large to microscopic. To better understand the size of a micron, note that a human hair is about 70 microns in diameter. The tiniest particles those smaller than 1 micron make up 99 percent of the particles in the air circulating within your home. Because the respiratory system's defense mechanisms (i.e. nose, sinuses and windpipe) are designed to filter out particles 3-5 microns in size, these tinier particles can be breathed deep into the lungs.

Breathing in these particles can have a negative impact on your health, ranging from irritation of the eyes and/or respiratory tissues to the potential of more serious long-term effects, such as decreased lung function and cancer. They can also trigger allergic reactions, asthma attacks and infectious diseases.

One way to help lower the particle count in your home is to use better air filters and change them regularly. Follow the manufacturer's instructions on the filter to see how often it needs to be replaced or cleaned.

Filters can be disposable or reusable and are made from materials such as fiberglass, metal, man-made or natural fibers. Factors that affect filter efficiency include fiber size, fiber density, airflow rate and particle diameter.

Types of filters

  • Panel filters, usually one-inch fiberglass filters, are the typical furnace filters installed in the ductwork of most home heating and/or air-conditioning systems. Although panel filters are used in 85 percent of American homes with forced air heating and central air conditioning, they do little to remove contaminants from the air. The primary function of these filters is to protect the fan and minimize the amount of dust on the heating and cooling coil. They also can capture large particles from the air. This basic filtering system may be upgraded by using a high efficiency filter to trap additional pollutants, or by adding additional air cleaning devices.
  • Washable/Reusable filters are designed to be washed and reused. They never get completely clean and can therefore restrict air flow. These filters are ineffective at capturing small particles.
  • Pleated filters are filters that have been pleated or folded to provide more surface area. These filters are typically more efficient than a panel filter. By increasing the surface area for collecting particles, the flow velocity of air through the filter is reduced, thereby reducing airflow resistance. It is important to change the filter on a regular basis so as not to restrict airflow.
  • High Efficiency Pleated filters have an electrostatic charge designed to capture tiny particles and allergens such as dust, pollen, mold, pet dander and smoke. These tiny particles - i.e. those less than one micron in size - make up 99 percent of the particles in the indoor air. High efficiency filters, such as Filtrete filters from 3M, are up to 30 times more effective than panel fiberglass filters in capturing these microscopic particles.
  • High Efficiency Particulate Air (HEPA) filters are extended filters that remove sub-micron particles with high efficiency. HEPA filters consist of a core filter that is folded back and forth over corrugated separators that add strength to the core and form the air passages between the pleats. The filter is composed of very fine sub-micron glass fibers in a matrix of larger fibers. These types of filters are not designed to fit most standard furnaces in homes with forced air heating and central air conditioning. Such homes generally need a separate system consisting of a fan and filter.
  • Electronic air cleaners use an electrical field to trap charged particles. Like mechanical filters, they can be installed in central heating and/or cooling system ducts. Electronic air cleaners are very effective, but they also can be quite expensive, costing up to $800 when installed. These filters can produce ozone and may require frequent (i.e. weekly to monthly) cleaning to maintain their effectiveness.

When selecting a filter, it is important to keep in mind that efficiency will change over time. As filters become loaded with particles, the available openings for air to flow through become smaller. The result is better filtration but less air movement, causing your furnace to work harder to move air through the system. That's why filters need to be replaced on a regular basis (follow manufacturers' instructions) to ensure proper airflow. As for electronic air cleaners, they are most efficient when first installed, and lose their efficiency as they get dirty. Regular maintenance and monthly cleaning is required to keep them operating at peak efficiency.

Tips on Using a Furnace Filter

  • Start by reading the manufacturer's instructions on maintaining your furnace to determine where the filter is located and also how often you should have your furnace inspected by a licensed heating contractor.
  • Read the instructions to identify the type of filter appropriate for your furnace.
  • When purchasing filters, look for the highest efficiency filter that works with your furnace (the higher the MERV rating, which is usually listed on the packaging, the better).
  • Replace your filter at the stated intervals, usually about every one to three months. Replace more often if you are introducing higher levels of particulates into your home, such as when renovations are being done, when using candles, if you have pets or if someone has been smoking in your house. Also, consider more frequent replacements if you have a family member with asthma, allergies or other lung diseases.
For other news editorials, see; electrostatic air cleaner.

Author Notes:

Nathan Coleman contributes and publishes news editorial to http://www.fresh-air-purifiers.com.  Learn more about air health and purifiers, plus allergies, molds and asthma and what to do about it.

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