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

hvac air filter that is dirty and not improving indoor air quality

Indoor air looks clean and clear, yet it is often filled with unseen indoor air pollutants. It is difficult to see these with the naked eye because of their small size but they are present everywhere. They can easily make their way into the house through tiny gaps. They can get into our lungs and cause trouble for our health. You might already be feeling some of their effects such as allergic reactions and breathing problems. Control the situation before it gets worse. Your current heating and cooling systems should already have air filters that are designed to capture these pollutants. However, these can perform poorly in certain situations. Let’s look at why your filters are not improving indoor air quality.

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Why Your HVAC Air Filter Is Not Improving Your Indoor Air Quality

An HVAC filter may not be working as expected because of the following reasons:

1. Air Filter Absence

image of moving day depicting hvac air filter absence

It is fair to assume that the HVAC system is complete with a filter in place. However, yours may be missing for whatever reason. If you just moved in, then be sure to check this before undertaking more advanced troubleshooting steps. Perhaps the last occupant removed the filter because it was already dirty. Letting the system run like this is not advisable since allergens and other particles can get inside without difficulties. The home will experience a quick build-up of dirt around the coils, blowers, and ducts. Place a fresh filter in the slot as soon as you can to prevent this.

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2. Incorrect HVAC Filter Installation

Air filters are simple products that are designed to let air flow through them while capturing air particles in the process. They should work flawlessly if installed correctly. Inexperienced homeowners may get this wrong, especially if they are not familiar with the system. Maybe the AC or heater they owned before had a different design. Perhaps they rushed the installation and created problems without being aware of what they did. For example, they might have left a small gap that allows dirty air to flow unfiltered. The result is poor indoor air quality despite the presence of a high-quality HVAC filter. The trained eye of HVAC technicians can spot this error while they are conducting regular maintenance.

3. Inadequate HVAC System Runtime

image of an hvac air vent

Filters are passive. They do not move or adjust to the current conditions. Air must flow through the filters for them to capture undesirable particles. The system enables the movement of air across the system. It should run long enough for the filter to do its job effectively. The problem with oversized HVAC systems is that they tend to turn off too fast. They can reach the ideal temperature quickly, automatically turning off before the filter has effectively caught pollutants. If you always experience short cycling, then talk to a contractor regarding your home’s heating and cooling needs. Perhaps they need to re-calculate to come up with precise numbers. Changing the fan settings from AUTO to ON can also help, as this forces the blower to work longer and keep air moving through the filters.

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4. Poor HVAC Airflow

If the system runs for adequate periods yet the airflow is limited, then you need to consider other solutions. The problem could be undersized return ducts, clogged filters, or both. Filters are at their most effective state at the beginning of the installation. As time passes, they catch more dirt and get more clogged. At a certain point, airflow gets so low that they need to be replaced. Otherwise, system efficiency will plummet while energy consumption will rise. Each filter is typically good for a few months depending on the level of pollutants in the environment. Homeowners should check its condition periodically and replace it whenever necessary.


5. Low MERV Rating

If the air filter is not improving air quality, then maybe you are using a product with a low MERV rating. Some people buy these items seeking bargain prices. The cheapest ones have low MERV ratings, which means that they are not that good at catching the smallest particles. In this case, you may want to switch to filters with a higher MERV rating and see if that makes any difference. You should get better performance out of them. You will probably have to spend a bit more on these but they will give you better value for your money. This makes them a worthwhile purchase, particularly if you are sensitive to allergens in the air.

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6. Bypassed Air Filter

Sometimes it is not just the filters that are incorrectly installed. The system itself may have a flaw in its installation because of inexperienced technicians. Despite getting a good brand of cooling system, you can still experience poor air quality because of the oversight. One example is a bypassed air filter, with the outdoor air duct connecting to the return side of the system. You won’t see this often but it happens. Homeowners might be clueless about it but experienced technicians will quickly spot the problem. With their help, you can finally perform the necessary corrections.

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7. Incorrect Air Filter Location

HVAC systems are designed to work in a certain manner. Air is meant to flow in a specific direction and this is important when installing an air filter. This item should be placed in the right location to produce optimal results. Refer to the manufacturer’s manual for more information. You can also discuss this with an HVAC technician.


Air filters have a major impact on indoor air quality. You cannot afford to neglect them. Being careless about these may result in health issues such as breathing problems, chronic coughing, and persistent sneezing. Check the air filter to see if it is exhibiting any of the items on the list above. If you are unsure, then solicit the help of a seasoned technician. Fix the problems found with the correct solutions. Use suitable filters with high-efficiency ratings and replace them regularly with fresh units. You and your family should feel the difference in no time.

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Wilcox Energy offers the finest HVAC services in the southern Connecticut shoreline. By working with us, you can count on one of our highly trained technicians to deliver superior service, each and every time. To ensure your satisfaction, we back our work with a solid guarantee. We are confident in their ability to deliver exceptional service whether you need HVAC repairs, tune-ups, heating and cooling replacements, installations, and more. They have done it all with excellent results.

Wilcox Energy keeps prices competitive so customers don’t need to hesitate when it comes to home comfort and energy efficiency. They can act immediately when problems arise thanks to budget-friendly and high-quality solutions. We provide suitable recommendations for every situation. If you wish to set up an appointment, then give us a call. We also offer free, in-home estimates.

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For more information about our HVAC services, be sure to contact Wilcox Energy. You can click here to contact us, or you can call us at (860) 399-6218 to find out more. We offer a full line of heating and cooling repairs, maintenance services, and installations.