Maintaining Your Central Air Conditioning System: The Filter

Air Filter

This is the first article in a three part blog series concerning your air conditioner. While we thought about skipping the whole air filter section, as most people are aware of this, we quickly learned differently when visiting Nathan’s house. His brother happened to be snooping around the air conditioner, and let’s just say that boy needs to read this blog! So as to not make any assumptions, here is the first air conditioning maintenance blog post, which covers air filters!

It won’t be long before the heat starts rolling in and your air conditioner will begin getting a work out again. If you take some time for routine maintenance, you can keep your cool friend running effectively and efficiently, increasing the life of your central air conditioning system.

Air Filter

One of the best things you can do for your air conditioning system is to routinely replace its filters. If you overlook this, the dirt and other impurities can not only be very unhealthy for you, but may also damage the air conditioner unit. You could be faced with health problems or very costly repairs that could have easily been prevented. Here are the steps you should take:

1. First, find your filter. Most central air systems use the same ductwork as the heating system. If so, your air conditioner usually shares a filter with your furnace. More than likely it will be covered with a metal panel in your furnace.  But, it may also be located in your ceiling, wall or floor. Find the size on the current filter to determine what size filter you need purchase to replace it. The size will look something like this: 12×14.

2. Purchase a new filter (or several). There are many different filters to chose from and they vary in how long the last until needing replacement. Also different filters offer different benefits such as hypo-allergenic filters for those of you who have allergies. In addition, most people don’t realize there are different types of filters out there offering different benefits. The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) hase been promoting the adoption of the minimum efficiency reporting value (MERV) system to standardize definitions of efficiencies of the different types. ERV measures a filter’s arrestance (a filter’s ability to remove large airborne particles from the air) and dust-spot efficiency (its ability to remove small airborne particles) and then assigns a number based on the filter’s ability to remove the particles. Several types of air filters are common in HVAC systems:

  • Fiberglass filter. This throwaway air filter is the most common type. Layered fiberglass fibers are laid over each other to form the filter media and typically are reinforced with a metal grating that supports the fiberglass to prevent failure and collapse.
  • Polyester and pleated filters. These filters are similar to fiberglass filters but typically have a higher resistance to airflow and a superior dust-stopping ability.
  • High efficiency particulate arrestance (HEPA) filters. These units filter the air passing through them at a very fine scale. The U.S. Department of Energy (DOE) and its contractors use HEPA filters that meet government standards to filter 99.97 percent of all particles 0.3 microns or larger.
  • Washable air filters. These products are not as common and rely on the build-up of dust along the cloth to improve the efficiency of the filter. Industrial processes involving high volumes of coarse dust are typical applications.

Keep in mind that you may need to replace more often if the system is in constant use or you have a lot of dust or pet hair in your home.

3. Remove the old filter and replace with your new one. Look for the air flow arrow on the new filter and make sure it is facing the correct way before inserting it into the system. Cover the filter with the metal panel, and you’re done.

While some filters last longer than others, a good rule of thumb is to replace your filter at least once every 30 days. This will keep your home’s air quality high and your electric bill low.

Up Next: The Evaporator

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