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Southlake Style

Air Filters - Aren't they all the same?

Oct 24, 2013 11:29AM ● By tina
Sponsored by Berkeys Air Conditioning and Plumbing 


We all know that we need to change the filters on our HVAC units regularly. We also know that changing them will save money on our utility bills, improve our air quality and keep that dusty coating off of our furniture. Yet we still forget to do it. When we do remember, do we even use the right type of filter? And all air filters are pretty much all the same, aren’t they?

Well, no, they aren’t. Each manufacturer and HVAC system has their own size filters for their equipment. So, before you run out and buy one, look on the HVAC unit, in the owner’s manual or manufacturer’s specifications. You can also bring the old filter to the store with you to find the correct size. But first, you have to find it. The air filter may be located in a grill in your wall or ceiling. These are commonly called return air filter grills. Or, it may be located in a slot on the side, bottom or top of your furnace (it depends on the type of furnace). Or, it might be inside the blower compartment of the furnace. This is common on older furnaces.

The differences don’t stop there. Other than the physical size of the filter, there are levels of filtration.  You have to look for the level that suits your home and family. Air filters have a standard rating system. The MERV (minimum efficiency reporting value) rating is a number from 1-16. For simplicity’s sake, the higher the number, the filter will stop more and smaller particles.

The lower levels of filtration will remove large particles like dust, lint, pollen, pet hair and dander. The next level will remove bacteria and mold spores in addition to the dust, lint, pollen, pet hair and dander. It will also remove smoke, microscopic allergens and particles that may contain viruses. The highest level will remove all that stuff as well as some particles containing odors. Air filters with the higher MERV ratings are sometimes called allergy filters.

Some manufacturers produce reusable or washable air filters. These filters usually have the lowest level filtration ratings. For some homes, this level of filtration is sufficient. And, if you don’t have allergies, you can save some money by using reusable or washable filters. 

The most common filter types are the disposable filters. Some are made with layered fiberglass fibers to form the filter media and typically are reinforced with a metal grating that supports the fiberglass to prevent damage or collapse. The quality of these filters varies greatly.  If you can see through them, they won’t filter out anything smaller than your dust bunnies and you’re wasting your money.  Make sure you’re getting a quality filter.

Another disposable type is the pleated filter, which has a MERV rating of 5-8. The pleated surface of the filter offers more surface area to catch the dirt and distributes the airflow more evenly over its surface. This means more dirt will be filtered out of your air. These filters are usually the best value in terms of price for the filter and keeping your HVAC system clean. 

The air filters made for the highest levels of filtration are sometimes made of advanced material. For example, electrostatic filters use an electrical charge to capture much smaller particles. Some other filters come with an antimicrobial treatment, which prevents organisms from living on the filter after they are trapped. For allergies, there are high-efficiency particulate air filters (HEPA). These filters remove virtually everything, but they can be expensive. Unless there is a specific reason to use them, the cost is an unnecessary expense for most homeowners.

You should choose the air filter that offers the highest level of filtration without damaging or over-taxing your HVAC system. Using a filter with a significantly higher MERV rating than the system requires or using a different type of filter can impact the efficiency of the system by decreasing its airflow.

Using the right air filter is only half of the answer, though. If it is not replaced often enough, your HVAC system operating efficiency will go down because the filter will become clogged. This will cost you on your utility bills as well as wear and tear on the HVAC unit. If your system can’t move the air through the filter, then the HVAC system isn’t doing its job.

Most HVAC service companies offer maintenance contracts, like Berkeys’ BAM Plan, which may include changing your filter for you. Companies like Berkeys can also perform a home energy audit and show you how to improve your home’s energy efficiency. 

You can call Berkeys Air Conditioning & Plumbing 24/7 at 817-481-5869 or email us online through our website for questions and scheduling information.