Does a dirty air filter affect air flow?

A dirty filter restricts airflow to your HVAC system's air handler. This restricted airflow places additional pressure on the air handler fan motor and could, over time, burn the motor and cause the system to overheat and ultimately fail. A clean air filter will not prevent airflow in and out of your unit. However, a dirty air filter will restrict the flow of cold air, causing it to build up inside the air conditioning unit and lower the temperature.

If the air filter becomes clogged during the summer cooling season, cold air buildup can cause ice to form on the air conditioning coils or evaporator. Freezing will reduce the HVAC system's ability to remove heat from the air and eventually cause the air conditioner to fail. Central air conditioning relies on continuous air recirculation. When that airflow is hampered by a dirty or clogged air filter, it means that your system has to work a lot harder to cool your home.

The harder the system has to work to extract air throughout your home, the more energy you need and the higher your energy bills will be. This inefficiency intensifies as the filter becomes more and more clogged. In a nutshell, every time your system is forced to work harder, it's costing you dearly (PLUS, you get less air for the money). As a result of the buildup, a dirty filter will also cause poor cold air flow in the air conditioning system.

That cold air will be trapped inside the air conditioner, causing ice to form on your coils. Once that happens, the air conditioner will freeze and stop working. However, before your system completely freezes, there will be some telltale signs you need to watch out for. One of them is the uneven cooling throughout the house.

If you notice that some rooms are harder to cool than others, while others are constantly feeling cold, you'll want to check your air conditioning filter first. A dirty air filter can break and damage the cooling system. Regularly replacing the filter and scheduling regular maintenance visits are good ways to keep your HVAC system running at peak efficiency. When your air conditioning system isn't working properly, the air inside your home can stagnate and become polluted.

Investing in routine maintenance can improve indoor air quality. The blower is not the most energy consuming part of the system, so that alone, the dirty filter causes a higher cost, as the system will need to run longer, but the blower itself will cost more due to the longer run time. If an accumulator fills your home with garbage, displacing enough internal air volume with static mass, the system will have to work harder to change the temperature when it finally comes to replacing the filter, which in all likelihood has been clogged for the past 6 months. If you have pets or have a lot of chemicals in your house, indoor air quality will be even worse with a clogged filter.

For the types of blowers most commonly used in these systems (squirrel cage with forward-curved blades for a large volume), the power used is dominated by the power to move the air. No matter what HVAC system you have, each unit needs a properly tuned quality filter to keep indoor air quality clean and keep your heating running at peak efficiency this fall and winter. If the filter becomes too clogged with dust, dander and debris, then the blower has to work harder to get air through a clogged filter. Without a filter, your unit will allow dust and debris to enter the internal components of your system, leading to potential catastrophic problems in the future.

If your HVAC system uses a disposable filter, be sure to replace it with one that is the specific size and design for your system. In fact, according to a study by the Florida Public Utilities Commission, the number two cause of high energy bills in the summer was air filter clogging. The air is then pushed into the heat exchanger (where it is cooled or heated again) and the circular cycle continues until the selected temperature is reached. If it doesn't cool your house as well as you'd like, the best first step is also the easiest: check your filter.

Don't let a dirty air conditioner filter stop you from feeling comfortable in your own home or lead to costly repairs. This will likely take 2-3 filter lifecycles to resolve, and will require things like my own AC runtime data, outside temperature, etc. In the US, servicing and replacing HVAC filters is one of the most important elements of regular maintenance of your heating and cooling system. .


Elisa Michocki
Elisa Michocki

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