If you install an air filter in the wrong direction, it can cause a number of problems. Air will struggle to flow through the filter material, causing your air handler to work overtime and waste energy. This can damage the air conditioner or heating system, and lead to a decline in indoor air quality. The filter is designed to remove a large amount of unwanted debris, but only when installed in the right direction.
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. 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. A furnace or central air unit that has to draw air through the non-porous side of a filter loses efficiency and runs longer, requiring more energy because it slows down the flow of air through the heat exchanger.
The result is an increase in your utility bill and additional wear and tear on your HVAC system. When a filter is installed in the wrong direction, it can quickly become clogged with dust, pollen, dander and other particles. So what happens if the air filter is improperly installed? 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. The most common problem you will have if you have an improperly installed filter is decreased efficiency.
Since the filter is designed to be efficient when installed in one way only, installing it incorrectly will make your system inefficient. One side of the filter is more porous to allow more air to flow freely. Therefore, when installing a filter backwards it would mean that your oven has to work harder to get the results you want. This will result in higher utility bills and may cause damage to your oven. You won't feel the effects of this at first, but this inefficiency can build up and lead to furnace system breakage and further repairs.
As if that weren't enough, the air quality in your living space will also decrease. When you place the air filter in the wrong direction, it cannot capture dust and air particles, and they will remain floating in the air. By installing the filter upside down, air will have more difficulty flowing through the filter and your air handler will have to work harder to compensate for the loss of airflow. Installing an oven or AC filter upside down is a breeze to do if you don't understand the return versus supply side HVAC loop. New homeowners or renters who don't understand the HVAC system well may have problems with this simple step of properly orienting the filter. Both sides may look the same, but filter manufacturers make filters so that air goes in one direction efficiently.
Also, if you look at where the filter is located, you'll see that air comes from one side of duct where there is no HVAC component. Air passes through an air filter, which (depending on its type) traps dust, dirt, and other airborne contaminants. This is because AC filters are designed in a way that allows for even distribution of dust within its material rather than just on its surface. In addition to looking at directional arrows, all filters are built in a certain way based on their type and how long they are designed to last. If you unintentionally install that filter upside down, then air will hit its fine-pore side first before it has a chance to enter it. The biggest damage that can result from a filter installed upside down is that it can damage your HVAC system and reduce its lifespan. HVAC filters come in different sizes; they can be 12-24 inches (30.48-60.96 cm) wide and 12-36 inches (30.48-91.44 cm) long.
Air filters have direction arrows indicating which way they should be installed on their return side. Having an inverted HVAC filter can cause system damage, mold problems, poor indoor air quality, and other issues. Even with proper maintenance of your filters, you should have your HVAC system cleaned and serviced at least once a year. Check your filters every month and replace them when you can no longer see light coming through them.
