My AC isn’t Blowing Air Out of the Vents

Step into a world of cool comfort with The Lee Thompson Co.’s trusted HVAC insights! With a legacy dating back to 1961, we have proudly served the Houston, TX community. Today, we’ll dive into a common issue that can leave homeowners feeling the heat: when your AC is running, but no air is coming out of the vents.

When your cooling system fails to deliver cool air, it can be frustrating and uncomfortable, especially during the scorching Texas summers. But fear not, our team of HVAC experts is here to guide you through the troubleshooting process step by step. From simple DIY fixes to knowing when it’s time to call in the professionals at Lee Thompson, we’ve got you covered.

At The Lee Thompson Co., we understand the importance of keeping your home comfortable year-round. That’s why we’re dedicated to providing you with the knowledge and support your need to keep your HVAC system running smoothly. Let’s tackle this AC dilemma together.

A large portion of issues with your air conditioning stem from these 2 causes:

  • Lack of Maintenance – Routine maintenance is key to keeping your system running efficiently for many years to come. Our Home Comfort Maintenance Plan offers affordable twice-yearly maintenance on your system to ensure small issues are identified and fixed before they lead to much larger issues.
  • Broken HVAC components – While routine maintenance is crucial to increasing the life of your system, you may still encounter broken or malfunctioning parts that require repair or replacement. A lot of these issues will go unnoticed until your unit stops working or air stops coming out of your vents.

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Here are the 11 reasons why your AC is running, but there is no air coming out of your vents.


  1. Check Your Vents
    If your AC is running and you are not feeling air coming out of your vents, you will first want to check all of your vents to see if you have an issue with just one or with multiple vents.

    If you notice a lack of airflow in just one area of your home, check to ensure that the registers in this area are completely open. Most vents have a switch or toggle to open and close the vents – you want to make sure that none of your vents have been inadvertently closed.

    You also want to check the vents for any obstructions that could be blocking the airflow. If you notice any, clear the obstructions and you will hopefully have fixed your issue.

  1. Thermostat Issues
    If you are still experiencing lack of air coming from your vents, your thermostat is the next likely culprit. Make sure that your thermostat is switched to ‘cool’, and that the temperature is set lower than the current temperature of your home.

    If you have a battery-operated thermostat, you will also want to check that your batteries aren’t in need of a change. Low or dead batteries can cause your thermostat to malfunction and not communicate effectively with your system and can ultimately impact your airflow.

    While at your thermostat, you will want to open the cover to check for any dust or debris that may be affecting your connection. You can remove any grime with a soft brush.

    If you notice any wires that are damaged or broken, it’s time to call in the professionals at The Lee Thompson Co. for a fix to get your AC back up and running –

  1. AC Blower Issues
    If you can hear your AC running, but the fan isn’t kicking on you will want to try lowering the temperature on your thermostat a few degrees. If your fan is still suspiciously quiet, this can be an indication of an issues with the AC blower.

    The AC blower pushes the cold air out to the ductwork and through your house. Excessive dust can accumulate on the blower blades and cause the blower motor to malfunction.

    To address this issue, turn off your AC and remove the covers on your indoor unit to expose the AC blower. Once open, gently wipe away any grime from the blower, replace the covers, and turn your AC back on.

    If your airflow is still lacking, give us a call at (713)766-4846 and we’ll send one of my HVAC experts out to properly diagnose and resolve this fan issue for you.

  2. Check Your Air Filter
    On the opposite side, if your AC and fan are both running and you still are not getting airflow through your vents, you will want to check for a dirty air filter. The air filter collects dust and debris and can block airflow through your system if not changed routinely.

    If left dirty and unchanged, it will greatly restrict airflow through your system and can cause your unit’s coils to freeze over.

  3. Frozen Evaporator Coil
    A dirty air filter or a blocked return vent can greatly restrict airflow through your unit and cause the evaporator coil to freeze over. When this happens, the air is blocked from passing over the coils and into your duct system to be pushed out through the vents.

    The first place that evaporator coils will freeze is within your air handler. If you notice ice forming on the lines or if they’re already frozen over, you will want to turn your thermostat fan to ‘ON’ instead of ‘Auto’ to help thaw the refrigerant lines.

    It’s very important that you do not chip away the ice or try to use a hair dryer to melt the ice. This can cause further damage to your unit.

    If you have changed your air filter and checked your return vents for obstructions and your evaporator coil continues to freeze over, it’s time for a call to The Lee Thompson Co. at (713)766-4846.

  4. Leaking or Blocked Ducts
    The ductwork is in place to deliver cold air throughout your home. With time and with lack of maintenance, your ductwork can become damaged or clogged. Issues with your ductwork can greatly restrict the airflow throughout the vents in your home.

    Have you done any recent work in your attic? This may have caused damage or a section of your ductwork to come apart.

    If you notice uneven cooling, dust in the air, or you notice twists in your ductwork, you will want to contact a professional at The Lee Thompson Co. or try to inspect the ductwork yourself.

    You will want to check for crack or holes within the ductwork as well as for leaks where the ducts join together. You will want to use foil-faced tape or mastic air duct sealant to seal any leaks or holes in your ductwork.

To check for ductwork blockage, you will want to check the airflow from individual vents to find any that are not blowing air at all. If you suspect a blocked duct, it’s best to call in the experts of The Lee Thompson Co. to efficiently resolve the issue –

  1. Over or Undersized Ductwork
    Incorrectly sized ductwork can also cause airflow issues throughout your home.

    Ductwork that is oversized will have a hard time maintaining air pressure and will result in low air pressure throughout your vents.

    Undersized ductwork will cause the airflow to be heavily restricted and will not be able to distribute it evenly throughout your home, which will result in low airflow from your vents.

    If you suspect an issue with ductwork sizing, give us a call at (713)766-4846 for proper inspection.

  2. Limited Return Air
    If your system is not receiving adequate air from your return vents, the air conditioning process will not work efficiently. To efficiently distribute cool air throughout your home, the same amount of air must return to be reconditioned and redistributed through the vents.

    You will want to check and ensure that the return vents throughout your vent are not blocked. If these vents are blocked, it can lead to a lack of air being pulled back into your system.

    If you are concerned that you don’t have the adequate amount of return air vents in your home, call on the HVAC experts at The Lee Thompson Co. at (713)766-4846 for a thorough inspection.

  3. Condenser Unit is Dirty or Damaged

    Leaves, dirt, and other debris can easily get stuck in your air conditioner’s outdoor unit. This will cause your unit to have to work harder and can lead to your unit overheating.

    Routine maintenance is key to ensuring that debris don’t accumulate in your outside unit and cause issues. We recommend our Home Comfort Maintenance Plan for affordable twice-yearly cleaning and maintenance that will ensure your unit continues to run efficiently for years to come. Visit or give us a call at (713)766-4846 to learn more.

  1. Low Refrigerant Levels
    If your refrigerant levels are low, you may notice low or no air blowing through the vents as well as reduced cooling throughout your home.

    A lack or AC maintenance can lead to corrosion buildup in your air conditioner. This buildup can cause cracks and holes in your AC coil and lead to leakage or your refrigerant.

    Call on The Lee Thompson Co. at (713)766-4846 to refill your refrigerant to ensure the levels match exactly with the levels specified by your AC’s manufacturer.

  2. Aging HVAC Unit
    A significant decrease in your air conditioner’s airflow can be an indication that your unit might be near the end of its life. Towards the end of life, a unit does not work as efficiently and cannot always maintain optimum airflow.

    Typical HVAC units last 15-20 years and up to 25-30 years with proper maintenance. Your HVAC unit will get less efficient as it ages. If your unit is older than this, one of our HVAC professionals can thoroughly inspect your unit and go over the best options for your individual needs.

    Give us a call to learn more at (713)766-4846 to learn more about our current specials and financing deals to get you into a new unit affordably.

If you have followed these troubleshooting steps and are still having airflow issues from your vents, it may be the sign of a bigger issues. There are a handful of issues that can limit the airflow to your vents and will require a call to The Lee Thompson Co. at (713)766-4846 to properly fix.

  • Indoor fan motor failure
  • Capacitor failure
  • Malfunctioning compressor
  • Mechanical problems

As you navigate the intricate world of HVAC troubleshooting, remember that The Lee Thompson Co. is always here to support you. Whether it’s a simple DIY fix or a more complex issue requiring professional attention, our team is just a phone call away – (713)766-4846.

Don’t let a lack of airflow leave you feeling hot under the collar – trust in our decades of expertise to keep your home cool and comfortable year-round.

Stay tuned for more valuable insights, tips, and tricks from the trusted leaders in Houston’s HVAC industry. Until next time, stay cool!

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