Can You Put an AC Filter in Wrong? - An Expert's Perspective

Installing an air filter incorrectly can have serious consequences for your air conditioner or heating system. Not only will it waste energy, but it can also damage the system and reduce indoor air quality. To ensure your system is running efficiently and safely, it's important to understand how to properly install an AC filter. When installing an air filter, it's important to pay attention to the directional arrows on the filter.

This indicates which side should face the air supply. If you place the filter backwards, the normally collective end of the device will not face the air supply. In fact, the filter will help keep debris in the air. When a filter is installed in the wrong direction, it can quickly become clogged with dust, pollen, dander and other particles.

Air filters are built to be installed in a certain direction. Installing the air filter backwards can restrict airflow through the air cleaner, cause the filter structure to fail, and allow dust, dirt, and other debris to pass through the filter and accumulate on the evaporator coil. If the evaporator coil becomes dirty, the system will not operate at optimal efficiency and could clog the condensate discharge line and cause the system to fail. All air filters have one side more porous than the other.

Porous side allows filter to trap airborne particles without restricting airflow through the air conditioner. If you place the filter backwards, air will have more difficulty entering the air conditioner and the unit will be forced to work harder to compensate for the lack of air flow. If you unintentionally install that filter upside down, the air will hit the fine-pore side first, before it has a chance to enter the filter. Instead of moving inside the filter and cleaning itself, the air will get stuck and then blow out the partially cleaned air on the other side.

Using an incorrectly sized air filter won't necessarily damage your HVAC system, at least not immediately. However, it has an impact. Using the wrong size reduces the efficiency of your heating and cooling system. This can add up quickly and becomes more of an apparent problem that you'll likely notice on your next utility bill.

A filter's fibers are designed to work efficiently in only one direction, allowing air to pass smoothly without interference. When an oven filter is placed upside down, the fibers cannot do their job properly. This means that your oven has to work harder to generate the same airflow, resulting in increased energy costs. Particles are also allowed to accumulate unevenly, causing the oven to work even harder to extract air. A small filter leaves gaps around the ventilation grille, allowing harmful particles in the air to pass through the air.

In addition to looking at the directional arrows, all air filters are built in a certain way based on the type of filter it is and how long it is designed to last. The biggest concern when using an improperly sized air filter is that it may not effectively prevent dust buildup on the motors and blowers of your HVAC system. Most fiberglass filters have little or no structure material, such as pleated filters woven into the filter material, except for a cardboard frame. It basically boils down to this: when an AC filter is installed upside down or backwards, it can greatly slow down airflow and make your oven have more difficulty operating. Air passes through the air filter which traps dust, dirt, and other airborne contaminants when installed correctly. However, when installed incorrectly these particles are allowed to build up in your HVAC system making it work harder than necessary. Installing an oven or AC filter upside down is a breeze if you don't understand how return versus supply side HVAC loop works.

To ensure your system is running efficiently and safely, it's important to understand how to properly install an AC filter.