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Filtration FAQs

Q: I was told that a filter's efficiency has something to do with a "MERV." What is this? What does this have to do with a filter's efficiency?
A: MERV (Minimum Efficiency Reporting Value) is a rating system on how well a filter performs in removing contaminants from the air. MERV ratings extend from 1 (bad) to 16 (best). Therefore, the higher MERV rating a filter has, the better it removes contaminants.

Q: How would I find out what my filter's MERV rating is?
A: Look on the filter. All good filters show air-flow direction and give a MERV rating. If your filter does not have this, then check the packaging.

Q: Is it important to know what MERV stands for? Why?
A: Yes. In the testing process, filters are tested in 3 separate categories: 0.30-1.00 microns, 1.00-3.00 microns, and 3.00-10.00 microns. Therefore, a MERV 8 filter may be 70% efficient @ 3.00-10.00 microns but negligible @ 0.30-1.00 microns range. It is very important to understand this because the smaller particles (0.30-1.00 microns) are ones not obviously seen and the ones most responsible for making us ill.

Q: What are some examples of micron size?
A: 0.3-1.00 microns=bacteria, fungi, tobacco smoke. 
    1.0-3.00 microns=pet hair, human hair.
    3.00-10.00 microns=hair, pollens, spores.  

Q: Does the filter affect air-flow?
A: Yes. The filter is 1 of several furnace components (refrigeration coil and ducting are other major components) that affect air-flow. Air-flow resistance varies greatly due to air volume being moved, size of filter, and filter construction.

Q: Does the filtration system also serve another purpose?
A: Yes. By filtering out particulates, lint and dust build-up on the heat exchanger and refrigeration coil is kept at a minimum. This enhances air-flow and reduces the likelihood of heat-exchanger related fire.

Q: I have an Electronic Air Cleaner. How efficient are they? Are there draw backs with EACs?
A: Please reference Manufacturer's information for details regarding filter efficiency. Some EACs have been associated with ozone production. Lennox Industries does not manufacture EACs.

Q: I have asthma. Is there a good filtration system for me?
A: Lennox Industries offers several choices: Healthy Climate media filter housing, PureAir Air Purification Unit, and HEPA filtration systems. The Healthy Climate media filter housing accommodates MERV 10, 13, and 16 filters. MERV 16 filters are the current pinnacle of efficiency. The PureAir Air Purification Unit incorporates a MERV 16 filter, UV lights, and metal catalyst. The HEPA system is a high-efficiency particulate air (HEPA) filtration system incorporates 3 components: pre-filter, HEPA filter, and charcoal filter. This system filters some 99.97% of 0.3 micron size particulates and can be used in conjunction with the home's existing filtration system, a Healthy Climate media filter housing, or PureAir Air Purification system.

Q: What drawbacks are there to better filter systems?
A: Obviously, the replacement filter(s) is going to be more expensive than a 'standard' 1" or 2" filter. However, they often last longer. When considered in the light of the increased health benefits, fewer coil cleanings ,and a cleaner house, the benefits make a quality filtration system worth investing in.

Q: We recently remodeled and, after remodeling, our family noticed increased headaches. Will a different filtration system assist us?
A: What you are describing sounds like VOCs (volatile organic compounds) from the off-gassing of the paint. A Lennox PureAir Air Purification system or HEPA filtration system will likely assist you greatly.