7 Reasons Your Filter Isn’t Improving Your Indoor Air Quality

hvac air filterIndoor air may seem clear and pristine but it’s filled with tiny particulate matter. You can sometimes see them visibly floating in direct sunlight. These particles are only a few micrometers long so they can enter narrow passages with ease. We breathe them in without realizing it and they penetrate deep into the lungs. If there are plenty of pollutants in the air, then our health can suffer over time. We can improve indoor air quality through filters that capture the particulate matter. However, heaters and air conditioners have built-in filters but these might underperform for one reason or another. If this is your case, then you need to determine why your HVAC filter isn’t improving indoor air quality.

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7 Reasons Your Filter Isn’t Improving Your Indoor Air Quality

An HVAC filter may not be working to its full capacity because of the following reasons:

1. No Filter

missing hvac air filter

Did you just move to a new house? It is reasonable to assume that the HVAC system is working as it should and that all the components are present. However, excessive dust and allergens in the air are rather suspicious. Check whether the filter is present or not. In some cases, the slot is left empty so dirty air passes through unabated. Perhaps the past owner forgot to put the filter back in. Maybe they found the spot hard to reach and gave up. This leads to fast dirt and dust build-up in the ducts, coils, and blowers.

2. HVAC Filter Installed Incorrectly

Having an HVAC filter is one thing. Installing it correctly is another. There is no use of getting a high-quality air filter if it is not in the right place. Even a small gap is enough for the dirty air to go around the filter instead of passing through it. As such, it will not be able to block particulate matter effectively. The indoor air quality will remain poor despite its presence. You can keep replacing it diligently as recommended by the manufacturer. However, the effort will not amount to anything until you improve the installation. Homeowners may not be aware that they are doing anything wrong but HVAC technicians are sure to catch this during maintenance work.

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3. Not Enough HVAC System Runtime

hvac air vent

Filters are static installations. In order for them to work, air must flow from one side to another. In other words, the HVAC system must run long enough to force enough air through the filters. Oversized HVAC systems are problematic because they reach the desired temperature too fast and shut off right away. Make sure to have a contractor calculate your exact heating and cooling needs to prevent improper sizing. Fan settings can also be changed from “AUTO” to “ON” to make it work longer. If you are still unsatisfied with the results, then consider getting a standalone air filter to focus on this task. Be sure to contact an HVAC contractor to learn more about improving your indoor air quality.

4. Not Enough HVAC Airflow

There are cases wherein runtime is fine but the airflow is limited. This results in reduced filtration volume. Undersized return ducts are usually the culprits. Clogged filters are another common cause for those who don’t follow the regular HVAC filter replacement schedule. If there is too much dirt on the surface, then air will have a hard time getting through. The air pressure will increase while the airflow will plunge. There is also a negative effect on system efficiency. Change the filters regularly so that they can block particulates effectively while letting clean air pass without any issues.

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5. MERV Rating Is Too Low

MERV stands for Minimum Efficiency Reporting Value. It’s an important filter specification that demands attention. Units will low MERV ratings are cheaper but they are not very effective in capturing air pollutants. Those with high MERV ratings can be expensive but you will be rewarded with excellent filtration performance. When shopping for new air filters, don’t reach for the model with the lowest price right away. Consider the value of money that you are getting with the product. It might be worth it to spend a bit more if you can breathe cleaner air and prevent respiratory issues when spending time indoors.

6. Not Filtering Outdoor Air For Mechanical Ventilation

HVAC systems are only as good as their installation. Getting a unit from a good brand will not matter if the designer botched up the plans or the installers made a mistake. For example, they might have connected the outdoor air duct to the return side of the system, totally bypassing the air filter. This is a rare oversight but it does happen. The keen eye of a highly experienced technician will spot this. It’s a frustrating problem to find but at least you will understand what’s happening and you can take the appropriate steps to resolve it.


7. Filter Is In The Wrong Location

You need to understand how the current HVAC system works and how the air is flowing to find the right spot for the air filter. You might think that placement would be trivial but people can make mistakes. Improper or sub-optimal placement will result in poor filter performance. Even the best models will fall short if they are in the wrong location.


The air filter is a vital piece of the indoor air quality puzzle. If your family is constantly sneezing, coughing, and having trouble breathing, then look into the HVAC filter. It may be exhibiting one or more of the issues discussed above. You need to get the right type and install it in the correct way. Prevent mistakes and fix issues right away with the help of a competent HVAC contractor. Have them perform a thorough system inspection and maintenance as soon as possible. You will feel the difference immediately.


Call McAllister Energy For All Of Your HVAC Requirements

McAllister EnergyMcAllister Energy offers superior heating and cooling services in Camden County, New Jersey. We hire the best-certified technicians who can provide you with excellent HVAC tune-ups, repairs, installations, and replacements. Each of our techs has the knowledge and experience to service your HVAC system correctly.

McAllister Energy guarantees the most competitive heating and cooling service costs in the area. Our maintenance services can improve your comfort, increase your energy efficiency while reducing your home cooling costs. If you happen to need an HVAC repair or replacement system, we can recommend the best one for your home while staying within your budget. We back all of our work with a guarantee to ensure your satisfaction. To schedule a service appointment, give McAllister Energy a call today. We offer free, in-home estimates.

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