Air filtration reference guide

Updated August 14, 2023
By Andrew Nickel | HVAC Supplier Development Manager

I’m sure we’re all fairly confident in the main purpose of air filters. Their job is to clean the air that enters your building through your heating and cooling systems. Right? They trap particulates and contaminants that effect the health and comfort of those in the building (think dust, dirt, dander, bacteria, microorganisms, etc.). In reality, filters were created to protect the equipment (i.e. air conditioner coils). Improved indoor air quality was just a happy accident.
 
But in order to truly ensure proper air filtration, you must understand the hazards you are protecting against, the types of filter media available, and what filter ratings mean. There are a wide range of filtration options available today to meet a variety of needs. Options range from inexpensive disposable panel filters to high-efficiency extended surface filters with antimicrobial capabilities, and everything in between. Use this reference guide to break down your options and find the best filtration options for your needs.
 
Before you can choose the right filter, you have to understand what you are up against.

• What types of contaminants are present in the facilities you are responsible for?
• Will you be dealing with dust from construction, chemicals from cleaning supplies, or viruses and bacteria from building visitors?
• Or is it a combination of contaminants?

You will need to choose your filter based on its rating, which is based on the filter’s ability to capture and hold the particles and pollutants present. The measurement used in these ratings is a micrometer, or micron, and refers to particle size.
 
Let’s put a micron into perspective.

MERV, or the Minimum Efficiency Reporting Value, as determined by the American Society of Heating, Refrigerating, and Air Conditioning Engineers, (ASHRAE) is the primary international air conditioner furnace filter industry standard and is used for rating the ability of an air filter to capture and hold particles and pollutants, like those laid out above.

In MERV ratings, the higher the number, the better the filtration. 
MERV 1-4: These are the most basic filters and provide a very basic level of filtration at a low cost. Common filters at this MERV rating are loose fiberglass, disposable panels, and washable metal filters.

MERV 5-8: (low to medium efficiency) These filters are commonly used in residential settings. MERV 5-8 are often extended filters, media panels, or paper and/or cloth pleats, the pleats providing more surface for filtering particulates. ASHRAE recommends using at least a MERV 8 or better when using a filter in an application with air conditioning coils.

MERV 9-12: Considered medium efficiency, filters in this range are of a higher quality and can capture very small particles of 1 micron or larger. Filters that fall into this category can be pocket filters, rigid box or cell filters, or cartridge filters.

MERV 13-16: These high-efficiency filters consist of ridge cell, v-cell, pocket filters, and H10-H12 HEPA and can remove very small particulates of 0.3 microns or larger.

>MERV 16: Filters above MERV 16 are referred to as HEPA (High Efficiency Particulate Air). These filters are able to trap 99+% of particulates that are 0.3 microns. HEPA filters are designed to perform in adverse, demanding, critical, and sensitive conditions, most common in medical/dental applications and require a specialized closed-air system.

You’ve determined the hazards and picked the best filter for your needs. Now all that is left to do is install your filters, right? Wrong. Unfortunately you can’t just set and forget your air filters. Make sure to follow manufacturer’s instructions, using your air quality as a guide, for proper filter maintenance.
 
Now you can breathe easy.

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Preventative
Maintenance Program
Though you likely have the best intentions in mind, without a set preventative maintenance schedule, you could be setting yourself up for costs you never intended to incur. Read on for some benefits of setting up a preventative maintenance schedule.

• Set up scheduled filter deliveries with your supplier to avoid higher freight charges incurred via buying online as needed.
• Have your filter in stock and ready when your preventative maintenance appointment is scheduled. This ensures you have what you need for a successful maintenance check and is another way to avoid unnecessary quick-ship costs.
• Set preventative maintenance appointments. These allow you to streamline the labor, since they’re intended to avoid paying emergency fees or pulling someone out of maintenance ad hoc.
• Filters need to be in stock on a set schedule to maintain optimum efficiency of your HVAC system. This allows you to save money on energy costs and improve air quality.

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