What Happens When You Put an Air Filter in Backwards?

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, causing it to clog and preventing the air from being cleaned properly when it reaches the lungs. The biggest damage that can result from a filter installed upside down is that it can damage your HVAC system and reduce its lifespan. An AC filter installed upside down will greatly slow down airflow, making it more difficult for your oven to operate.

This decrease in efficiency increases the likelihood of a system failure, such as a refrigerant line leak or a failed compressor. Air filters are built to be installed in a certain direction, and installing them 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. Oven filters are designed to allow air to flow in one direction through the filter media.

When efficiency decreases, this can cause dust to accumulate on the blowers and motors inside the furnace. Turning the air filter upside down from time to time isn't likely to cause damage to the system, but it can cost you money in efficiency. 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, so 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. Dirty ducts will cause you to replace air filters sooner than normal. And finally, the air passes through the high-efficiency HEPA filter to trap the smallest particles with an efficiency of 99.97%.

If no air filter is present in the air return, these airborne contaminants end up accumulating in the evaporator coil. As a central heating and cooling system owner, one of your most important maintenance responsibilities is to regularly change your air filter. This is because a dirty, clogged air filter will significantly impair the efficiency of your oven and air conditioner. Most air cleaners have arrows printed on the sides that act as indicator marks pointing to the direction of airflow.

Try not to shake or hit the old filter, as this could release particles back into your home's air. Check your filters every month and replace them when you can no longer see light coming through them.