MERV Ratings: How They Impact Your Workplace Air Quality
Maintaining indoor air quality in the workplace is important not only to comfort but also to customer and employee health and safety. The air filters in your HVAC system are your primary line of defense against the airborne particulates and pollutants that can cause discomfort, trigger respiratory conditions, or spread disease. When choosing the type of air filter you put in your facility’s furnace, air conditioner or heat pump, it is vitally important that you understand the concepts behind MERV ratings.
What is MERV?
MERV means Minimum Efficiency Reporting Value, and is a measure of filter efficiency that is well accepted throughout the HVAC industry. The rating indicates how well a filter can remove airborne particles ranging in size from 0.3 to 10 microns. Standard filters have MERV ratings ranging from 1 to 16, with higher MERV numbers indicating greater efficiency at removing airborne contaminants.
Air filters remove contaminants and particles from your indoor air as the air circulates through your HVAC system. They commonly capture and hold particulates such as dust, pollen, fibers, metal fragments, hair and other solids that can be inhaled or that can contaminate surfaces. HVAC filters can also trap microorganisms such as viruses, bacteria, mold spores and germs that can spread disease or trigger allergies or asthma attacks. Filters are available with activated charcoal inserts that absorb gases and fumes.
The more filtration you want for your workplace, the higher MERV rating you should choose.
- MERV 1-4: Filters at MERV levels of 1 to 4 are usually low-cost, but are minimally effective. Their best performance is in collecting particulates of 10 microns or larger. They are not recommended for use in workplace HVAC systems.
- MERV 2-8: Medium-quality filters have MERV ratings between 2 and 8. They are usually made of pleated cloth or other material that presents more surfaces where particulates can be collected. They work best on material of 3 microns and larger.
- MERV 9-12: These are high-quality filters and are going to be effective in most residential or commercial settings. They capture particles of 1 micron and larger.
- MERV 13-16: These high-MERV filters are the best quality available that will work in most HVAC systems. They can remove material of 0.3 microns and larger.
An important point to keep in mind is that higher-MERV filters are very thick and dense, which can affect the performance of your HVAC system by restricting the airflow. If airflow is limited, it can damage the fan and air handling system, which could lead to costly repairs. Check your HVAC system warranty to see if there are any limitations on the MERV levels that can be used. If you want to use higher-MERV filters, have your HVAC professional test the system and see if it can handle thicker filters.
In some cases, you may want or need air filtration that goes beyond standard MERV levels. If so, HEPA (High-Efficiency Particulate Air) filters may be your best solution. HEPA filters provide air filtration at MERV levels of 17 to 20. They are effective at removing up to 99.97 percent of the solid particulates from indoor air, up to and including microorganisms, smoke and powders.
HEPA filters are often used in settings where air quality is critical, such as medical facilities, computer clean rooms, and manufacturing plants where sensitive electronics or similar devices are made. They are sealed, self-contained units that require specialized mountings, installation procedures, and ongoing maintenance. As with other filters at the high end of the scale, make sure your HVAC system can function with HEPA filters before making the transition.
Our goal is to help educate our customers about Plumbing, HVACR, Fire Protection, and Alarm Systems in Mechanical, Commercial and Residential settings. For more information on HVAC filters and MERV ratings, what MERV numbers mean to your indoor air quality and system performance, or to view projects we’ve worked on, visit our website!
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