What Happens When You Install an Air Filter the Wrong Way?

Installing an air filter incorrectly can have serious consequences for your HVAC system - from reducing indoor air quality to damaging components and increasing energy costs.

What Happens When You Install an Air Filter the Wrong Way?

Installing an air filter in the wrong direction can have serious consequences for your air conditioning or heating system. Not only will it waste energy, but it can also reduce indoor air quality and damage the system. The filter is designed to capture a large amount of debris, but only when installed correctly. If you set the filter upside down, the normally collective end of the device will not face the air supply.

This means that instead of trapping debris, the filter will help keep it in the air. 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 upside down will greatly slow down the flow of air, making your oven have more difficulty operating. When efficiency decreases, the likelihood of a system failure, such as a refrigerant line leak or a faulty compressor, increases.

The air quality inside the living space is also affected when an oven filter is installed incorrectly. The filter cannot capture dust particles when air moves through the filter in the wrong direction, so that unwanted debris ends up floating in the house instead of being trapped by the filter. So what happens if the air filter is improperly installed? 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 fibers of a filter are designed to work efficiently in one direction only, allowing air to pass smoothly without interference. When an oven filter is placed upside down, these fibers cannot do their job properly. This means your oven has to work harder to generate the same airflow, resulting in increased energy costs.

Particles are also allowed to accumulate irregularly, making your furnace work even harder to extract air. While inserting the air filter in the wrong direction may not damage the system, it will reduce its efficiency and cost you extra money. If you unintentionally install that filter upside down, the air will hit the fine-pored side first before it can enter the filter. Instead of moving inside the filter and being cleaned, the air will get stuck and then blow out partially clean air on the other side.

Because your air conditioner or boiler will have a harder time drawing air through the filter, this can impair its efficiency and eventually damage its components. Keep in mind that your filter only gets dirty when your oven is working, so if you are checking it in a holiday home that you only visit a couple of times a year, for example, replacing it might not be a monthly chore. Basically, when you install an air filter correctly, it should be more porous (larger holes) on one side so that it can trap larger particles first before gradually filtering out smaller dust particles. Check your filters every month and replace them when you can no longer see light coming through them. Your oven draws cold air from your house, heats it through a heat exchanger and returns warm air to your living space. If there is no air filter in your return ducts, these airborne contaminants end up accumulating in your evaporator coil. Air filters have directional arrows printed on them to indicate which way they should be installed on your return ducts.

In addition to looking at these arrows, all filters are built differently depending on what type of filter it is and how long it is designed to last. HVAC filters come in different sizes; they can be 12 to 24 inches (30.48 to 60.96 cm) wide and 12 to 36 inches (30.48 to 91.44 cm) long. Some filters even capture smaller particles such as those that cause allergic reactions in people so as to keep your living space as clean as possible.