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Complete Guide to Buying HVAC Air Filters

The one-stop-shop on Air Filters- why YOU need them and which types to get!

Far and away the most overlooked part of any apartment, office, or house is the quality of the air within. HVAC (Heating, Ventilation, Air Conditioning) systems pump air into the house, changing the temperature and intensity when necessary. However, the quality of the air goes unregulated by most, if not all HVAC systems. The air quality is controlled through air filters. Air filters, as the name suggests, filter the air coming in through the HVAC systems to keep it clean, pure, and healthy.

This article has two sections, and both are important to your air filter experience. The first section explains the basics of air filtration within the HVAC systems of your residential or commercial space, whether house, condo, room, office, conference room, or any other type of indoor space, air filters are necessary for everyone indoors and the first steps to understanding that are explained there. The second, instead of talking about why air filters are something every household should take care to buy, it instead goes into detail on the next steps. Once you realize that you need air filters within your various spaces, how do you go about getting them? What kinds of air filters are out there and which type of filter is the best for your situation? The second section acts as a down-to-earth guide on understanding the different types of air filters out there, clarifying which filters do what, and what filters are the best for which situations.

In short, this is the only air filter guide you will ever need.

Air Filters- what they are, what they do, and why you need them:

Bearing a passing resemblance to window screens, air filters share largely the same purpose: To keep unwanted objects out of the indoor airspace. However, unlike window screens, which mostly stop bugs or leaves, air filters catch the smallest microbes and particles just a few micrometers wide- stopping them in their tracks. The air filters are the essential barrier between you and the millions of small microbes looking to climb through your HVAC systems and into your breathing space.

That last point raises a good question about the relevance of air filters. If air filters have the job of stopping only the smallest of materials, are they really that important? Everyone breathes unfiltered air outdoors, what is wrong with it? What is so bad about the outside air?

The truth is that there is nothing wrong with the outside air itself, but that is because there is a lot of open space outdoors, so there is not much room for those particles to accumulate to less than healthy proportions. To illustrate the necessity of air filters, imagine a house. It can be as big or small as you please, just as long as it is in a typical suburban neighborhood on a typical day.

Look at that house. Visualize the HVAC systems as tunnels into the outside world, as air passes through them, allowing those inside to breathe comfortably. Keep breathing, but know that besides the clean air, there are a few other things, too. There are some small pieces of lint from the next door neighbor’s shirts drying on the clothesline. The old lady down the street who likes to walk her cat that sheds hairs left and right, invisible to the naked eye, swept right up into the HVAC systems. Add to that some pollen, causing allergic reactions, maybe some construction materials from the house across the street, a few spare fleas from the dog scratching itself in front of your house, and maybe some mold along the side of your other neighbor’s stucco house… still breathing?

Although invisible, there are many different contaminants within the air of the outside world. Outdoors, the open space mitigates the contamination, refusing to allow it to accumulate enough to pose a threat to your health. Indoors, however, the closed space makes everything worse, allowing the accumulation of unhealthy particles within the air coming out of the HVAC systems.

That accumulation can reach staggering proportions. According to the EPA, the air indoors can be up to five times more polluted than the air outside. As well, several studies have linked many health issues to a lack of air filtration, such as difficulty breathing, aggravated asthma, irregular heartbeats, and heart attacks. Unfortunately, plain HVAC systems, though powerful, do not seem to bring in completely safe air while unfiltered. They require proper air filters to bring in optimal air, breathable air that will not put the structure’s occupants at risk.

Everybody wants to inhale pure and clean air. Whether for health or cleanliness reasons, it is an essential part of any household, office, or apartment. More importantly, nobody wants to have to think about the quality of their air. People breathe about 22,000 times a day, and it is likely that many of those people do not want to think of the purity of the air they are breathing in. Thankfully, a simple way to ensure you, your family, guests, workers, and anyone else within your atmosphere is breathing fresh, clean air, and not worried about breathing in contaminated air, is to install air filters in your ventilators. That way, all of those outside contaminants will be trapped, caught by the filter, as strictly pure air is filtered in. Air filters will ensure that everyone indoors is breathing safer and healthier air.

Which types of filters do what?

Now that we clarified why air filters are so important, the next step is figuring out how the different types of air filters out there compare and hold up against each other. Each type, from fiberglass, to polymer, to pleated, have their purposes, though the fiberglass and polymer filters typically share the same qualities, especially when compared to the pleated filters, which differ drastically from the other two categories.

Each filter is good for certain situations. Pleated filters are stronger, more durable, catch smaller particles due to typically higher MERV ratings, yet are also more expensive and more restrictive in terms of airflow. Non-pleated filters, on the other hand, allow for more airflow at the cost of more particles getting through, though they may have shorter life spans than their pleated counterparts. Below the qualities of pleated filters and non-pleated ones will be compared and contrasted to help you find the right filter for your situation.

In terms of price, the non-pleated filters are leagues cheaper than their more expensive counterparts. 

It’s the classic window-fly dilemma: The AC in your room is broken, and it is the hottest day of the year. You want to open up a window, as it’s a hot day, but there is a nice breeze, and the wind from the outside will help alleviate some of the sweltering heat in your room. However, if you crack open a window in your room, a fly waiting by the door might sneak its way in, disrupting all your activities in a desperate bid to kill it. And if you cannot kill the fly, it will buzz right in your ear at 2am that night, as you jump right out of bed from the noise. The fly can only get into your room if you open the window, so what do you do? You can leave the window closed and wallow in the heat, you can admit defeat and leave the room, or, you can take the risk and open the window, knowing that along with the cooling breeze of the outside air, you may also let in a few unwanted visitors.

This, in a nutshell, is the window-fly dilemma, and it parallels the different types of air filters quite well.

The pleated filters are comparable to leaving the window closed. Yes, your air is more contaminant-free, but because of the inherent restrictive nature of the pleated filters, the air coming in from your HVAC system will become a lot more constrained. Less air will be in the room as a whole, because the normal air flow was disrupted.

The non-pleated filters are what happens when you open the window. By opening the window, you are letting in more air into your room than you would have had if you kept the window closed. However, keeping your window closed, in the end, is the safer play. And because you opened up the window, letting the air from your HVAC system flow freely, you inadvertently might let a few unwanted guests into your airspace as well. These guests are not bugs per say, (though they can be small parts of bugs) but smaller particles that can cause health problems to the more fragile occupants of the airspace. Those small particles more colloquially known as coarse particles for the ‘larger ones’ (about ten micrometers or less) and fine particles (less than 2.5 micrometers) are responsible for many unfortunate health problems. As put by the official government page of Alaska:

Numerous scientific studies have linked fine particle pollution exposure to a variety of problems, including:

  • increased respiratory symptoms, such as irritation of the airways, coughing, or difficulty breathing;
  • decreased lung function;
  • aggravated asthma;
  • development of chronic bronchitis;
  • irregular heartbeat;
  • nonfatal heart attacks; and
  • premature death in people with heart or lung disease

Nobody wants to see their loved ones hurt for just breathing in the air around them, it is damage that nobody can actually see. Because of that, people who are housing elderly occupants, people with more fragile health situations, typically purchase the pleated filters because they are able to protect against those smaller fine particles leagues better than the non-pleated filters. For the average person, breathing in those particles is not the best thing, but it does not seem to be fatal. For these people however, with more delicate health situations that require almost every element of their environment to be carefully curated, maybe the pleated filters may be the better choice, and the way of quantifying which filters are the best for that type of situation are by looking at the MERV ratings.

As mentioned above, the pleated filters tend to have higher MERV ratings. MERV (Minimum Efficiency Reporting Value) ratings on their own are a bit technical as a concept, but for the basic know-how regarding purchasing air filters, what you need to understand is that the MERV rating system is, for our purposes, between MERV level 1 and MERV level 16, each level correlating to higher efficiency and filter strength. The higher the MERV level, the smaller the particles the filter can catch, typically ranging in the micrometer range. Lower MERV levels, however, tend to lead to less expensive filters, and higher airflow, which can prevent the HVAC system from burning out, as it tends to do with some of the higher MERV levels.

To learn more about MERV levels and the specifics of each tier, as well as the numbers and science behind air filters and preventing disease, check out this article on Mastering the MERV to broaden your understanding of air filters beyond the basics.

MERV levels aside, the important aspect to take away from them is that the pleated filters have higher MERV levels. And the higher the MERV level, the better the filter’s overall performance, but its cost and airflow rates go down.

Again, as said in the beginning of this section, your choice of pleated versus non-pleated air filters is really dependent on your specific situation, what you believe, based on your factors economic-wise, health-wise, and occupant-wise, what the right filters are for you. We can’t help you determine which filters are right for you because we don’t know your specific circumstances and what you are willing to spend. Though, once you figure that part out, we can offer you some help on the purchasing side, making it easy to find the correct filter, because ours are customized. With Custom Filters Direct, you can choose the quantity and quality of the filters utilizing our website. We offer the ability to customize the sizes of our filters to fit your ventilation systems, and are happy to ensure you have the clean and pure air you deserve. Not only that, but we have an automated delivery system, so when, inevitably as we all do, you forget to replace your filters, you will have new ones just waiting on your doorstep! Order online today, ensuring that your air is the best it can be.