For filters installed in a ceiling or wall return, the arrow should face the ductwork, meaning it should point in the direction of the ceiling or wall. This helps guide the air smoothly through the filter entering the HVAC system.
Position the airflow arrow so that it points in the direction the air is flowing. In addition to clean air, filters also protect your HVAC system from debris and dirt buildup. The airflow arrow should point towards the furnace/blower motor to collect harmful particles before it reaches the furnace's equipment.
If your filter is on the ceiling, the arrow should face the ceiling. If your filter is on the wall, the arrow should face the wall.
It will decrease the efficiency of the air filter and reduce its durability. In worst-case scenarios, it can also cause a complete system failure.
All furnace filters have arrows around the edge that indicate the direction of the airflow. The arrow on your air filter should point towards the blower in your HVAC unit. This ensures that the filter catches particles and debris before they enter the system, protecting the internal components from damage.
If your filter uses air flow direction arrows, make sure these arrows point toward the cabin, aligning with the air movement from the outside into your vehicle. If your filter uses UP and DOWN arrows, the UP arrow should face upwards, which typically means the air flows downward into the cabin.
If the filter goes inside the ductwork, it should point toward the air handler or the furnace. If you're using a filter that doesn't have an arrow but does have a mesh coating on one of its sides. The thinner or lighter side on unmarked filters always goes toward the air handler, furnace, or blower compartment.
If you have a combined heating and cooling system and need to decide between placing the return vents high or low, consider your climate. If you live in cooler climates, it might be wise to install them towards the floor, whereas if you reside in warmer areas, they should ideally be installed close to the ceiling.
Here's an easy way and simple guideline to follow: When installing the air filter in the HVAC unit, ensure the arrow should always point towards the blower. This direction ensures that the air flows through the filter material correctly, thereby effectively trapping the particles.
The arrow points in the direction that the air is flowing. It does NOT point toward where it's coming from! It points toward where it's going to! It doesn't matter if the vent is an outlet or a return.
The most common problem you will face with a backwards facing filter is simple inefficiency. If your furnace is forced to blow air through the non-porous end of a filter, it will take more energy to do so. The blower will be overworked and you will pay more money for your heating.
The best method to accurately measure airflow is with an anemometer. This device has been a standard for many years, and it measures air speed and velocity by using cups attached to a spinning device. The air moves the cups, which are connected to a sensor that reports various data points.
Air filters have arrows printed on the sides of them that show you which way they are supposed to be installed. These arrows should be pointing in the direction that air flows through your system, which is away from the supply ducts and (typically) toward the blower.
In general, you need to take a static pressure measurement on the return and supply side of the air handler. This kit is designed to easily and quickly perform this test. Compare this measurement to the manufacturer's max static pressure value. If the TESP is too high, it indicates there's an airflow issue.