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What to Do When your Air Conditioner Air Flow is Weak

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Have you found that your air conditioner isn't blowing hard or has a weak airflow? On a Summer day your air conditioner can be your best friend or your worst enemy, and there's nothing worse than coming indoors and finding that the air just isn't moving through your AC as it should or even worse, you could face your ac not turning on. 

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When your AC is running, but very little air is coming out of the vents, you have an airflow problem. There are several different issues that can cause low or weak airflow in an air conditioner. But before calling a professional, try to diagnose the problem yourself. 


Reasons Your AC System Has a Weak or Low Airflow

Some of the solutions are surprisingly simple. In fact, there's a good chance  you can fix this yourself and save the expense of hiring a repair service. Here's the six primary reasons your air conditioner isn't blowing air through your vents as it should. 

AC Air Filter

The reason your AC has weak airflow could be as simple as changing your air filter. An air conditioner draws warm air in, cools the air and then blows it back into your home. When the air filter is dirty, the air conditioner needs to work harder in order to move the air thru this cycle.

Air filters should be changed as needed, but it's a best practice to check them every month. This video will show you how to change an air filter and perform other maintenance tasks on your air conditioner.

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Kink in the Flex Duct

It's possible that you have a kink or a tight bend in your flex duct work. If this is your problem, the amount of air coming out of your vents will definitely be restricted.

You may need a professional to solve this problem, but it's not a difficult task if you have access to your duct work. Duct work is often routed through an attic, crawl space, basement ceiling or a garage. Simply follow its path and look for kinks. This video shows the differences between rigid and flex duct work.

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If you have a portable air conditioner that doesn't need a window, then you wont have a duct.

Blocked Return Vent

If your air conditioner isn't getting enough incoming air, it definitely won't be able to deliver enough cool air. This is an easy fix.

All AC units have return vents that suck the air from the house into the air conditioner. If there's an obstruction, such as a bed or a couch located over the return vent, it won't be able to suck enough air back into the unit. This can result in your AC not blowing hard. Simply find the return vent and move any obstructions.

Evaporator Coil

If it's been awhile since you've changed your filter (or worse, run your AC with no filter at all!), it's possible that your evaporator coil is dirty and needs to be cleaned.

In order for your air conditioner to complete the cooling process, air is blown over the evaporator coil. When the evaporator coils become dirty and clogged the airflow is blocked. When the airflow is blocked you'll notice a weakened flow of cool air coming from your vents. You could even notice your air conditioner keeps running when turned off, which is another sign of an issue with your evaporator coil. 

Although you can clean your evaporator coil yourself, we highly recommend hiring a professional.  

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Duct Leaks

If your duct system has disconnected joints or is leaking because it's not fully connected, your air conditioner is most likely working fine, it's just not able to deliver the amount of cool air expected. This is because air is escaping through your duct work.

It's estimated that the average house loses up to 30% of the air that passes through the duct work due to poorly connected ducts, holes or other leaks.

If you have access to your ducts you may be able to fix this on your own or you may simply want to hire a professional.  This video shows several examples of duct leaks and how they can be repaired.

Watch the Video

DIY AC Duct Repair

Are you a DIY kind of person who's interested in tackling this project yourself? Below are some of the supplies you'll need: 

Design Polymerics 1030 Water Base Duct Mastic Sealant Pail 0.50-Gallon
Design Polymerics 1030 Water Base Duct Mastic Sealant Pail 0.50-Gallon
Low to high velocity air duct sealant, Color- Gray; Used for permanently sealing sheet metal and flexible duct system joints
Glasscoat® Adhesive-Backed Fiberglass Mesh 3' X 180'
Glasscoat® Adhesive-Backed Fiberglass Mesh 3" X 180'
3 inch by 180 feet Roll - 10 x 10 Mesh; Coated One Side with Pressure Sensitive Adhesive; Reinforces Joints & Seams Sealed with Mastics & Sealants
Great Stuff 175437 Insulating Foam Sealant, 12 Oz, Yellow
Great Stuff 175437 Insulating Foam Sealant, 12 Oz, Yellow
The product is 12OZWind/DR Foam Sealant; Distinctive Yellow Foam; The product is manufactured in United States

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AC Blower Fan

If your blower fan isn't working properly it won't be able to blow enough air through your vents. There's a number of issues that can cause your blower fan to reduce it's output air flow, but here are the most common:

  • Broken or warn fan belt
  • Clogged with dirt
  • A stuck wheel
  • Dead motor

When the blower fan has problems, your air conditioner does too. Many people prefer to hire a professional to make this repair, but depending on your comfort level, you may be able to fix this yourself.

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Last update on 2024-03-13 / Affiliate links / Images from Amazon Product Advertising API

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