What is MERV?

If you have an HVAC system in your home or business, you probably have a general understanding of how they work. The system moves air both in and out of the building and either cools or warms the interior. The HVAC system contains air filters to trap particles as it draws in air. These particles include dust and allergens, but also microorganisms too small to see with the naked eye. What you may not be familiar with is the MERV rating on air filters. We’ll answer the question of What is MERV and why it matters to indoor air quality.

What is Indoor Air Quality?

The HVAC system works hard to heat and cool buildings but it also helps maintain healthy indoor air quality or IAQ. Proper IAQ helps create a healthier indoor environment whereas poor IAQ can lead to health problems. Poor IAQ affects asthma and allergy sufferers. It may lead to Sick Building Syndrome in office workers. It’s also been linked to lower cognitive functioning in school children. In short, maintaining proper IAQ is important. Therefore the HVAC system’s ability to remove allergens and pathogens from the air is important too. Air filters are key to this.

What is MERV in Filters?

You may have seen or heard the term MERV rating in reference to air filters. You may have asked What is MERV? MERV stands for minimum efficiency reporting value. Its rating tells you how effective an air filter is at removing particles and stopping contaminants from spreading. A high rating means a more effective filter in trapping small particles. For example, a filter with a MERV rating of 17 through 20 is very effective in removing small particles. This makes them better suited for hospital operating rooms. A filter with a MERV rating of 16 or below is better suited for residential or commercial building use.

The HVAC systems installed in many homes have a MERV 8 rated filter. Upgrading to a higher-rated filter provides cleaner air. For example, a higher MERV-rated filter would improve the effectiveness of the system in preventing particles from circulating in the home. This includes pathogens such as viruses, mold, and bacteria. Using a higher-rated filter could potentially impact the performance, however. Before you upgrade, check the HVAC manual or talk to an HVAC professional. 

What is HEPA in Filters?

In addition to What is MERV, many people are confused about what a HEPA filter is. HEPA stands for high-efficiency particulate air (filter). HEPA filters are effective in removing particles as small as 0.3 microns. In fact, HEPA filters remove up to 99.97 percent of airborne particles including pollen. 

Of course, with a filter this efficient, you might think they would be used in all HVAC systems, but there is a drawback to HEPA filters. The filter is filled with interwoven glass fibers. The thickness and dense construction of these filters can actually degrade their performance in an HVAC system. This is why many homeowners purchase stand-alone air purifiers to supplement air filtration. In addition to the HEPA filter, some of these devices use UV light and carbon filters to provide additional protection.

Air Purifier Efficiency

In addition to understanding what is MERV, it’s helpful to know what air-cleaning devices do. Air purifiers reduce the number of airborne particles both at home and in offices and smaller commercial spaces. It’s important to find the one suitable for a particular room. Correct placement gets optimal performance. The efficiency of an air purifier increases by up to 20 percent with proper placement.

You also need to find one to match the size of the room. For example, the AeraMax Professional 2 is a good choice for commercial use in rooms 150 and 300 square feet. This device features a 4-stage filtration system, a true HEPA filter, as well as a carbon filter that reduces odors. The device also features sensors that detect motion so it can adjust to room conditions. The Dyson TP04 Pure Cool Link is a good choice for residential use and provides over 77 gallons per second of airflow.

Buy MERV-rated Air Filters

We hope this answers your questions about what is MERV and how it impacts indoor air quality. To learn more about air cleaning technology or to order an air purifier, give us a call at 727-572-4550.