Air Filter Types

There are many types of filters in the market to choose from for your home, but which one is right for you and your home? Determining which filters you should use really depends on your specific needs as all filters have pros and cons.

Usually, when choosing filters you are choosing between cost and filtration ability. Quite often, more expensive filters exhibit more complex construction and are able to capture finer dust particles, allergens, and other pollutants.

Inexpensive filters perform less particulate filtration and are generally designed for the protection of your HVAC system. As you move down the product line to more expensive filters, you will find they attempt to perform two key roles:

  1. Protecting your HVAC
  2. Removing dust, allergens, and other particulates from the air.

Filters are rated according to which particulate they are able to capture and their dust holding capacity. However, this is where things get confusing. There isn’t just 1 rating system for filters, many rating systems exist! Filters will commonly display a number rating accompanied by one of the following standards to rate the filter:

  1. MERV/ ASHRAE 52.2: Introduced in 1999 Read more on MERV Ratings https://www.nafahq.org/understanding-merv/
  2. ISO 16890: The new global ISO standard introduced in 2017 to replace MERV/ASHRAE https://www.iso.org/obp/ui/#iso:std:iso:16890:-1:ed-1:v1:en
  3. FPR (Filter Performance Rating): A rating system unique to The Home Depot
  4. MPR (Micro-Particle Performance): A rating system created by 3M

Read more about how each rating system stacks up to one another here.

Filter ratings are often dictated by the construction and material of the filter. These are the common types of filter construction that you will find in the marketplace:

Fiberglass filter: A disposable filter that is comprised of fiberglass fibers laid over one another to form the filter media. Typically this filter is reinforced with a metal grating or weaving for support to prevent failure and collapse. Often these filters are the most inexpensive but perform less fine particulate filtering than all other filter types.

Polyester & Pleated Filters: A disposable filter that is made of pleated polyester or similar synthetic medium. These filters contain pleats and may also feature cardboard or metal meshing to maintain structural integrity. The benefits these filters have are that the available surface area for filtering is far larger than flat filters. This benefit allows for finer particles to be trapped by the filter, yet still, maintain the necessary air flow for your system. Pleated filters can effectively filter out pollen, dander, dust mites, mold, and bacteria.

Electrostatic: Some filters are electrostatically charged to pick up particles. This does not mean that they are electrically powered, but they contain a charge that acts a lot like a magnet, allowing the filter to attract particles and make them stick. These types of filter excel at removing fine particulates

HEPA (High-Efficiency Particulate Arrestance): Homeowners often see these types of filters in vacuums or specialty air purifiers. These filters are almost never used in HVAC applications because they impede airflow for HVACs. HEPA filters exceed all other filters for contaminant filtration and are commonly used in hospitals, clean rooms, and airliners. HEPA filters carry a MERV rating of 17-20.

Washable Air Filters:

Washable filters are made of durable materials that can be washed and reused again. These are a cost-effective long-term filtering solution, but typically carry a MERV rating of 1 to 4. They work well at filtering large particles but are ineffective for smaller particles such as pet dander, bacteria, viruses, and smoke.

Conclusion

You should now have a basic understanding of filter options that are available in the market. Next time you make a filter purchase, you will be well equipped to purchase the right filter for your specific environment.