Air Filtration

Air Filtration

Most of us want to make healthy choices for ourselves, and our families, but we seldom think about the air we breathe. According to the CDC (Centers for Disease Control and Prevention), Particle Pollution can affect anyone. Particulates account for about 35% of Indoor Air Pollution. The level of particles in the air bothers some people more than others. Remember, there is more to living healthy than eating good food, rest and exercise.

When it comes to purchasing air filters, it’s easy to become confused. Well, UV Shield is here to help you understand the role of air filtration in Indoor Air Quality and provide you with important information about how innovation is improving air filtration and reducing HVAC operating expenses too.

Image: Poor Indoor Air Quality

What are Arrestance, DHC, MERV, MPR, and FPR and why should I care?

These are different rating scales for Air Filters and help customers determine the right filter for their HVAC System. Understanding these scales can help residential and business consumers determine what type of air filter will best fit their home or business’s needs.

Arrestance Rating

Arrestance is just a fancy word for filtering capacity. More specifically, Arrestance is a measurement of an air filter or filtration devise’s ability to remove dust from the air. The test is used by ASHRAE, the American Society of Heating, Refrigeration and Air Conditioning Engineers to quantify how well a filter or device can remove ASHRAE dust (synthetic dust used for testing) from test air. These Arrestance measurements correspond with how well an air filter removes real-world larger airborne particulates like dirt, lint, hair, and dust.

NOTE: As Arrestance goes up, airflow goes down. This is important to keep in mind because it means your HVAC system is working harder and using more energy! Too much Arrestance can cause your air conditioner’s evaporator coils to ice up or your heater to overheat potentially damaging your heating and cooling system! While Arrestance is tested, the value is seldom reported for values above MERV 4 (see below).

DHC Rating

The Dust Holding Capacity of an air filter is commonly abbreviated DHC and like Arrestance it is seldom reported on filters with values above MERV 4.

MERV Rating

The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) established MERV ratings in an effort to create a worldwide standard rating system. MERV is short for Minimum Efficiency Reporting Value. On a scale from 1 to 20 the MERV tells the consumer how effective a filter is at trapping airborne contaminants such as dust, pollen, and pet dander. The higher the MERV rating the smaller particles are filtered from the air.

The CDC recommends a MERV rating of 13 or higher to reduce the spread of SARS-CoV2 the virus that causes COVID-19 but most HVAC systems can’t handle the Arrestance of a MERV 13 filter and replacing your heating and cooling system is very expensive. However, UV Shield offers several cost-effective alternatives to replacing your entire HVAC System. One true “Hospital Grade” solution is our Bypass HEPA Filters. We also offer near Hospital Grade solution called a Polarized Filters and Air Cleaners.

Keep in mind that MERV is the “minimum” ability for the filter to trap particulates when it’s first installed. As the filter traps particulates, its ability to stop even smaller and smaller particles from passing through increases. But as the Arrestance rises it becomes harder and harder for your HVAC system to circulate the air.

Breathing fresh air sounds like a great idea, but all too often consumers purchase a high MERV rated filter without knowing if their HVAC system can handle it. Most residential systems function properly with a MERV rating filter from 6 to 11.

Generally speaking, the higher the MERV rating, the more often the filter needs to be changed. Yet many consumers think that a high MERV rating means they don’t need to change the filter as frequently.

FPR Rating

The home improvement chain The Home Depot created their own rating system called FPR which stands for Filter Performance Rating. This system is based on their independent scientific testing. It was intended to establish a unified ranking system, but many find it overly simplistic. Additionally, FPR is only used for Honeywell Filters and other brands sold at The Home Depot stores, yet some of the best filters on the market are not available in their stores.

MPR Rating

The 3M company created its own rating system called MPR, which stands for Microparticle Performance Rating. It was created to rank their 3M Filtrete brand filters’ ability to catch the small airborne particles. MPR is helpful when comparing one 3M Filtrete filter to another, but there currently is no cross-reference for MPR, FPR, MERV, DHC or Arrestance.