How do you know which way the air flows?

Asked By: Maricruz Schomburg | Last Updated: 17th January, 2020
Category: home and garden indoor environmental quality
4.1/5 (29 Views . 29 Votes)
In other words, the air travels from the tail of the arrow toward its point. If there is no arrow, the side that is stronger or reinforced by cardboard or wire mesh is the side the arrow should be pointing to. Air flows from the weaker side to the stronger side.

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Similarly, how do I know which way the air flows in my AC?

If you are looking at a furnace filter, find the arrow that indicates the proper air flow direction. That arrow must always face toward the furnace and away from the return duct that carries the air in need of heating or cooling.

Beside above, what if I put my furnace filter in backwards? If you put your filter in backwards, the usually collective end of the device will not face the air supply. Your filter will aid in keeping debris in the air. This results in a clogged filter and inaccurately cleaned air getting into your lungs.

Moreover, which way does air filter go in?

Luckily, most filters are made so they won't fit right unless they're inserted in the correct direction. There should be airflow arrows printed on the side of the air filter to indicate what direction the filter should be inserted. When you insert your new filter, the arrow should point toward the furnace.

Is MERV 11 too restrictive?

A decade ago, it used to be that if you had an HVAC system that used panel filters rated 6 through 9 MERV, putting in a MERV 11 or higher filter would restrict airflow (known as filter pressure drop). In turn, this would lengthen the system's run-time, adding to your heating and cooling costs.

22 Related Question Answers Found

How do I fix the airflow in my house?

Here are some of the tasks your HVAC technician can take care of to improve the HVAC airflow in your space:
  1. Perform HVAC airflow measurement and testing to determine the severity of the problem.
  2. Clean or replace air filters.
  3. Clean fan blades.
  4. Inspect & adjust motors.
  5. Inspect your ductwork for blockages or leaks.
  6. Clean coils.

How do you put an AC filter in?

Check out our easy, step-by-step installation instructions:
  1. Remove the plastic from the filter—don't remove the cardboard framing.
  2. Find the airflow arrow and point it toward the AC/heating blower.
  3. Insert the filter into its slot [central unit].
  4. Insert the filter into its slot [wall unit]

What is the return duct?

Supply air ducts and return air ducts are two separate halves that make up the whole of your heating and cooling air distribution system. Return air ducts draw air out of each room through a separate air vent and convey it back to the central unit to be reheated or cooled.

What MERV rating is best for home use?

Better residential filters (5-8 MERV rating) will filter common household allergens such as dust, pollen, mold, and pet dander, while superior residential filters (9-12 MERV rating) will help to remove such things as cigarette smoke, which are more difficult to filter because they contain smaller particles.

How do I change the air filter in my house?


  1. To Change Your Home Air Filter, You'll Need To Turn Off Your Furnace.
  2. Find and Locate Your Furnace Filter.
  3. Determine the Size of Your Home Air Filter.
  4. Remove the Existing (old) Air Filter.
  5. Insert the New Air Filter.
  6. Return furnace to “on” position.

Which direction should ceiling return air vents face?

If you have an Air Return is on the upper wall I like to slant the louvers upwards so that floor traffic does not view into the duct opening. That is the same with Supply vents as well IF you have adequate air flow and few cold or hot spots in the room from inadequate air flow or distribution.

Which way does airflow on a furnace?

Remove the old air filter from your furnace. On your new air filter, find the arrow that indicates the proper air flow direction. This tends to confuse everyone more than anything else. That arrow must always face toward the furnace and away from the return duct that carries the air in need of heating or cooling.

Should you put filters in air vents?

Do not put filters in your supply vents. Your AC system should have a proper fitting filter on the return side. By placing a good fitting, high quality filter on the return vent, you will remove particles from the air before they can enter the AC system.

What happens if you use the wrong size air filter?


Incorrect Air Filter Size
Another issue that can lead to reduced indoor air quality and put a strain on your air conditioning and heating system is when you use the wrong size air filter. HVAC air filters come in all different sizes.

Do pleated furnace filters restrict airflow?

Because they restrict airflow to your HVAC system. Pleated, high-MERV filters definitely capture a lot of pollutants, but they also restrict the movement of air into your blower or furnace. These cover all the air filtration basics - dust and pollen removal, for example - without restricting airflow.

Can you run a furnace without a filter temporarily?

If you run a furnace without a filter for one night, it won't affect your HVAC system detrimentally. However, the longer you run your heating system without an air filter, the more contaminants will accumulate inside your heating unit inner mechanisms.

Does a dirty filter affect AC?

A dirty air filter restricts the flow of cold air, causing it to build up inside the air conditioner and lower the internal temperature. Uneven Cooling: Even if it's not enough to cause freezing, that restricted airflow isn't good for your air conditioner's cooling power.

Can I run AC without filter?

Your air conditioner will run without a filter, but you shouldn't try it! Without a filter, you leave your system wide open to all types of dirt and debris that will damage the HVAC system and lead to expensive repairs.

Why does my furnace filter gets black really quick?


Carbon monoxide: This odorless, invisible gas is the byproduct of incomplete combustion and can cause soot deposits on your furnace filter. This can transfer to the dirt and dust collected on the furnace. If left wet long enough, black, sooty mold can begin to grow and spread to the furnace filter.