Which Side of Air Filter Faces Out?

Replacing the air filter in your home is an important task that should not be overlooked. Not only does it keep the air clean and free of allergens, but it also helps the airflow in your home function more efficiently. Still, proper installation is key to ensuring the airflow through your filter stays unrestricted.

The front side of the air filter (the side without the mesh) faces out. In other words, the air filter should be positioned such that the arrows printed on it point toward the unit. This way, the backside (the side with a mesh covering) faces the unit.

In this post, I will teach you how to replace the air filter in your home and explain why it’s essential to do so regularly. I’ll also provide tips on maintaining your air filters for optimal performance.

How To Install an Air Filter?

Making sure that you take all the right steps to install your air filter properly is one sure way to help your HVAC system work efficiently and create high-quality airflow in your home. Follow the steps below for a proper and seamless air filter installation:

  1. Start by identifying your air filter’s front and back sides. The side with the mesh should face toward the unit, while the side without the mesh should face outwards.
  2. Turn your unit off so that you don’t accidentally do any damage.
  3. Remove any existing air filters from your home’s HVAC system or furnace. If your air filter is attached to the side of the HVAC system using a frame, you may need to take off any outer panels or housing first.
  4. Once you have removed the old air filter, place the new filter into its proper position inside the unit. Ensure it is level and that no mesh is peeking out from underneath.
  5. Once your new air filter is in place, close up any housing or panels you had to remove earlier and turn on your HVAC system or furnace.
  6. Check to see if the airflow feels smooth and unobstructed, and adjust your air filter as necessary until it does.

The video below gives a step-by-step guide to the air filter installation process:

What Happens if You Install an Air Filter Incorrectly?

If you install your air filter incorrectly, it can cause a variety of negative consequences for your HVAC system or furnace:

  • Reduced airflow. With reduced airflow comes reduced heat and cooling capacity, which can result in higher energy bills due to your unit having to work harder to maintain the temperature of your home.
  • Increased wear and tear on your HVAC system or furnace. This damage over time will potentially lead to expensive repairs down the road.
  • Increased allergens and other pollutants in your home’s air. These can be harmful to your health and aggravate existing respiratory conditions.
  • Increased strain on your unit. Over time, this strain can cause your unit to break down prematurely, leading to costly repairs or replacements.
  • Unwanted particles will be drawn into the system. These particles can cause damage to the internal components of your HVAC system or furnace.
  • Reduced lifespan of your HVAC system or furnace. Failure to install an air filter correctly may mean you will need to replace it sooner than expected.

To avoid these negative consequences, it is crucial that you install your air filter correctly and maintain it regularly. This can be done in a few simple ways:

  • Replacing the filter on a regular schedule.
  • Ensure that the filter is level and not blocking the airflow.
  • Keep your unit clean of dust or other particles.

If you notice any issues with your HVAC system or furnace, addressing them as soon as possible is also crucial to prevent further damage.

Dirty hvac filters

Read: Why Does My Central Air Have Two Filters?

10 Signs It’s Time To Change Your Air Filter

Here are some common warning signs that it may be time to change your air filter:

  • The filter looks dirty or clogged with debris. If the filter has a lot of dust, dirt, pet hair, or other particles on it, it is likely that the filter itself has become clogged and needs replacing.
  • The airflow coming through your vents seems weak or restricted. If you notice that there is less airflow coming from your vents than usual, this could be a sign that your air filter is clogged or damaged.
  • You notice an increase in allergy symptoms or asthma flare-ups. If you are experiencing more frequent bouts of sneezing, coughing, itchy eyes, or other allergy symptoms, there is likely a buildup of allergens and other particles in your home’s air supply.
  • An increase in mold or mildew growth in your home. Mold and mildew thrive in environments with high humidity levels and poor airflow. A clogged air filter exacerbates these conditions.
  • An increase in dust or other airborne particles around your home. A clogged air filter can lead to the accumulation of dust and other particles in the air, making it more difficult for those particles to be filtered out by your air filter. If you notice that furniture, curtains, rugs, and other items around your home are collecting more dust than normal, take a look at your air filter.
  • You notice an increase in energy bills or other HVAC-related issues. A clogged or damaged air filter can impede the airflow coming from your HVAC system, which causes it to work harder and consume more energy than necessary.
  • An increase in the time your HVAC system takes to heat or cool your home. If your air filter is dirty, clogged, or damaged, this can cause the HVAC system to take longer than expected to heat or cool a space.
  • You notice an increase in noise coming from your HVAC system. A clogged air filter can cause the vents and fans in your HVAC system to work harder, which may create more noise.
  • You must have your HVAC system or furnace repaired or replaced more often than usual. If you notice that your HVAC system is breaking down or malfunctioning more frequently, you may have a clogged air filter on your hands. Regularly replacing the air filter helps prevent these problems and keeps your HVAC system running smoothly.

If you are experiencing any of these signs, it is likely time to change your air filter and keep your home’s air clean and healthy. Remember to check your air filter regularly, and be sure to replace it according to the manufacturer’s recommendations.

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Read: Does Air Handler Have Filter?

How Often Should You Change Your Air Filter?

Most air filter manufacturers recommend changing your unit’s air filter every three months. However, the frequency with which you should change your air filter will depend on a number of factors. These include the type of filter you have, the severity of dust and other particle buildups in your home, and how often you use your HVAC system or furnace.

Generally speaking, you should aim to replace your air filter according to the manufacturer’s recommendations. However, you may want to consider replacing it more frequently if you are experiencing any of the signs listed above.

Read: Furnace Filter Airflow – What You Need To Know?


If you are looking for ways to keep your home’s air clean, your first priority should be changing and maintaining your air filters regularly. Taking these steps can help prevent allergies and other health issues caused by airborne contaminants in your home’s air supply.

Additionally, there are other things you can do to keep your home’s air clean, including maintaining your HVAC system, cleaning and vacuuming regularly, and keeping your windows closed when possible. With these tips, you can enjoy a healthy home environment that is free of allergens and other airborne contaminants.