What Happens When an Air Filter is Installed Backwards?

Installing an air filter upside down can cause serious damage to your HVAC system and reduce its life expectancy. Learn what happens when you install an air filter backwards.

What Happens When an Air Filter is Installed Backwards?

If you install an air filter upside down, the normally collective end of the device will not face the air supply. This results in a clogged filter and poorly cleaned air when it reaches the lungs. The biggest damage that can result from a filter installed upside down is that it can damage the HVAC system and reduce its life expectancy. An AC filter installed backwards will greatly slow down the flow of air, causing your oven to have more difficulty operating.

When efficiency decreases, the likelihood of a system failure, such as a refrigerant line leak or a faulty compressor, increases. Air filters are designed to be installed in a certain direction. Installing the air filter backwards can restrict airflow through the air filter, 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 optimum efficiency and could clog the condensate discharge line and cause the system to fail.

The biggest problem with installing an air filter upside down is that the oven has to work harder to do its job. One side of the filter is more porous than the other. An oven or central air unit that has to suck air through the non-porous side of a filter loses efficiency and works longer, requiring more energy because it slows the flow of air through the heat exchanger, according to Bob Vila. The result is an increase in your utility bill and additional wear and tear on your HVAC system.

Most air filters have arrows printed on the sides that act as indicator marks pointing to the direction of air flow. Oven filters keep oven mechanisms clean while removing pollutants from the air you breathe. It basically boils down to the fact that the filter was designed to be more porous when air first impinges on the filter (to trap larger particles) and less porous on the outlet side (to trap small dust particles). These filters will last for about 3 months, however, they may fail, causing the filter frame to bend or even bend in the return box.

Even with proper air filter maintenance, you should clean and repair your HVAC system at least once a year. This makes sense because you want the air to be filtered before it reaches the actual furnace equipment and covers it with dust. And finally, the air goes through a high-efficiency HEPA filter to trap even smaller particles with an efficiency of 99.97%. The supply side is made up of smaller branch ducts that supply air to each room through ventilation grilles. The filter also cannot capture dust particles when air moves through it in reverse direction.

Some filter designs even capture smaller particles, such as those that cause allergic reactions in people, to keep indoor air quality as clean as possible. The fibers of a filter are designed to work efficiently in one direction only, allowing air to pass smoothly without interference. If you have an air return on your ceiling or wall that uses a filter, make sure that its arrow points towards it. Having an inverted HVAC filter can lead to system damage, mold issues, poor indoor air quality and other problems.