What Type of Air Filter is Most Efficient?
The air filters in your HVAC equipment make an important contribution to the indoor air quality of your commercial establishment. Their most important role is to capture and hold airborne contaminants such as dust, mold, pollen, fibers, and other material that could get into your indoor air. When choosing air filters to put in your furnace, air conditioner, or heat pump, pay particular attention to their efficiency ratings.
Why Would You Want a High-Efficiency Filter?
The simplest reason to want high-efficiency air filters is that higher efficiency filters are much more effective at cleaning your indoor air than lower efficiency types. Cleaner indoor air creates a more comfortable working environment for your employees and a better shopping experience for your customers. Stale, malodorous, or dusty air at your commercial location could harm your business’s reputation and make customers unwilling to shop with you. You could also want a high-efficiency air filtration system if you are involved in certain types of businesses. High-efficiency air filters are commonly used in environments such as:
- Medical clinics, hospitals, treatment rooms, operating rooms, and other areas where patient comfort and health are important considerations.
- Computer clean rooms containing delicate electronics, servers, storage disk arrays, or other technology that could be affected by particulates in the air.
- Manufacturing facilities that produce or test sensitive electronics, material that must be kept free of contaminants, or substances that produce odors and fumes that could affect employee comfort and health.
- Food production facilities that require sanitary environments for handling, processing, and packaging food items.
High-MERV and HEPA Filters
Air filter efficiency is indicated by the filter’s MERV rating. MERV stands for Minimum Efficiency Reporting Value and is a measure of how effective a filter is a trapping and holding particulates. Standard MERV ratings span a range from 1 to 16, with higher MERV numbers meaning better filter efficiency. HEPA, or High-Efficiency Particulate Air, filters have even higher MERV ratings, ranging from 17 to 20. These filters are extremely efficient and are used in cases where air quality is critical. They can remove almost all of the particulates in your facility’s indoor air. Lower-efficiency filters are commonly made of spun fiberglass that looks like a mass of threads.
Higher-MERV filters that are better at cleaning your indoor air are usually made of pleated cloth or other dense material that is better at trapping particulates. The pleats in the filter medium provide more surface area for the capture of particulates and contaminants. Higher-efficiency filters may also contain inserts of activated charcoal or other material that removes fumes and odors.
Remember that high-efficiency filters are very thick and dense and could interfere with the airflow in your HVAC system. They may also require specialized mountings or, in the case of HEPA filters, entirely separate filtration systems. Make sure your HVAC system can handle a high-efficiency filter before installing one. Otherwise, the air flow blockage could damage your heating or cooling equipment. Other Efficiency Ratings In addition to MERV ratings, there are other efficiency measures that affect how well a filter will work in your HVAC equipment.
Initial and sustained efficiency: The initial efficiency rating indicates how well a filter works when new, while sustained efficiency measures how well the filter will work over time.
Pressure drop: Also known as filter resistance, this indicates the effect the filter will have on airflow within the HVAC system.
Dust holding efficiency: This is a rating of how much dust the filter can hold at a specific pressure drop.
Arrestance: Arrestance is a laboratory-determined rating of how well a filter captures and holds dust particles.
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