Understanding the Types of HVAC Air Filters

Spring brings warmer weather but it also brings allergies. One simple yet often overlooked practice that can have a significant impact is changing your air filters regularly. Selecting the correct HVAC filter is crucial for maintaining indoor air quality and optimizing the performance of your HVAC system. With numerous options available, understanding the factors to consider can help you make an informed decision.

In this comprehensive guide, we delve into the importance of this routine task, its benefits for indoor air quality and system efficiency, and how you can make it a part of your HVAC care routine.


How Do Air Filters Work?

Air filters work by forcing air to pass through a filter medium like foam, pleated paper or fibrous mesh. These filters fit into pre-made slots inside the air ducts of a home or building’s HVAC system. As the air passes through, particles and contaminants are captured within the filter. The filtration process depends on the specific type of air filter.

Air filter maintenance is an ongoing household management task for a homeowner. Changing filters every month or two, depending on needs, helps to keep a ventilation system clean consistently over time. This ensures that the air quality within the home or office environment stays at high quality levels.


The Importance of Clean Air Filters

The air we breathe directly impacts our health and well-being. When air filters become dirty and contaminated, they fail to effectively trap particles and debris circulating in your home or business. As a consequence, the air quality is compromised, exposing occupants to potential health risks, especially those with allergies or asthma.

To foster clean and healthy air, it is important to change your air filters regularly. By doing so, you not only ensure that harmful particles are filtered out effectively, but you also safeguard the well-being of your family, employees, or customers. Investing in high-quality air filters with proper filtration capabilities is essential for maintaining indoor air quality and reducing the risk of respiratory issues caused by airborne pollutants.


Types of HVAC Air Filters

While there are many types of air filters you can buy for your home, fiberglass and pleated are the most common residential filters. Both fiberglass and pleated air filters serve their purpose and provide many benefits for your home but differ in a variety of ways.


  • Fiberglass Air Filters

Fiberglass air filters are an economical choice and are widely prevalent in many households and establishments. Constructed from layered fiberglass fibers, these filters trap larger contaminants such as dust and debris. However, their efficiency might not be top-notch regarding finer particles, allergens, or bacteria. For those seeking basic air filtration, fiberglass filters are a reliable pick. Yet, they might fall short of environments demanding more thorough air purification. Nevertheless, they are excellent pre-filters in advanced multi-filter systems, enhancing their overall efficacy.


  • Pleated Air Filters

A pleated air filter uses screens of polyester, plastic fibers, or cotton to remove dust and other particles from the air that enters the HVAC system. Unlike standard filters, they have pleats, or folds, which offer more surface area for filtering more debris that could otherwise destroy the AC coils or blower fan. As an added advantage, pleated filters improve indoor air quality.


Finding Your Filter Size

Size matters when choosing the right air filter for your HVAC system. Finding the right size air filter is important to ensure the filter fits properly and performs efficiently. Air filters come in many sizes, and various HVAC systems require filters of varying dimensions – you can’t simply pick one up at your local big-box store at random.


There are three easy ways to determine the size of your air filter.


  1. Refer to the label on the filter’s frame

The easiest method is to remove the existing filter from its slot and look for the size printed on the frame. However, keep in mind that the size listed in bold on the frame is the filter’s nominal size, which may differ from its actual size. If the actual dimensions are not listed, it’s a good idea to measure the filter to double-check.


  1. Measure your air filter

If you cannot find the size on the filter, you can simply measure it yourself using a ruler or any other measuring device. Measure the length, width, and depth of the inside edge of the air filter’s slot or frame.


  1. Measure your air intake

This method is a bit more challenging but can provide accurate measurements. First, turn off your AC system to ensure safety. Then, use a measuring tape to measure the length, width, and depth of the inside edge of the air filter’s slot or frame.


What Is a MERV Rating?

Every furnace filter has a Minimum Efficiency Reporting Value (MERV) rating, which measures how efficiently the filter captures particles of specific sizes that pass through it as your furnace operates. MERV ratings range from 1 (least efficient) to 16 (extremely efficient). Particles are measured in microns and range from carpet and textile fibers (greater than 10 microns) to microscopic bacteria (less than 0.3 microns).

To determine MERV ratings, air filters are put through two primary tests: The Dust Spot Efficiency Test, which measures the ability of the filter to remove atmospheric dust particles from the air, and the Arrestance Test, which measures the filter’s ability to remove synthetic particles that have been injected into the air for testing purposes. Most high-quality filters can remove 90% or more of injected particles from the air in the Arrestance test (in other words, they do a good job of removing what they’re expected to). Because atmospheric dust applies equally to all filters, Dust Spot Efficiency varies widely.


How to Make Your Selection

When deciding on the right home air filter, focus on these factors:


Household needs: Pet owners, people with allergies or asthma, and homes in dusty or high-pollution environments may do best using a filter with a higher MERV rating.

System compatibility: Before you upgrade to a higher rated filter, make sure your HVAC system can handle it without hampering airflow.

Filter thickness: 4- to 5-inch-thick filters usually work longer and offer stronger filtration than standard 1-inch filters.

Cost vs. benefits: High-end filters cost more up front but need to be replaced less often and provide higher air quality.

HVAC professional’s advice: The best way to make an informed decision is to speak with an HVAC technician offering reliable advice based on your home’s system and air quality requirements.


When Should You Clean or Replace Your AC/Furnace Filter?

The answer is, it depends on your filter and whether you have an air purification system. How often to change an air filter will depend on filter type, usage, and environmental factors. Plan on changing a standard 1” filter at least every 90 days. You may want to switch to changing it every 30 days if you have high system usage, allergies, or pets. You may also want to consider upgrading to a better filtration system.


Signs of a Dirty or Clogged Air Filter

There are several signs of a dirty or clogged filter you should be aware of.

  • Visible Dust Around Vents
  • Increased Dust in the Home
  • Allergy or Respiratory Issues
  • Decreased Airflow
  • Increased Energy Bills
  • Uneven Heating or Cooling
  • Ice Buildup on the Evaporator Coils
  • Strange Odors
  • HVAC System Overheating



Final Thoughts

If your air conditioner is still not running properly and you are not experiencing better air conditioning efficiency after completing the above tips, it might be time to call a professional service technician at Aire-Tech. Our highly trained and skilled technicians will check your unit or units for proper air flow and coolant levels as well as clean internal coils and perform other repairs if required.

If your system needs repair or inspection before spring or summer, call us on 951-926-1002. You can also visit our Contact page and complete the contact form.