AC Not Blowing Cold Air: 5 Reasons Why This is Happening

Is your AC not blowing cold air? The last thing you want to do is wake up or come home and discover your air conditioner is not working properly. Not only is this very uncomfortable, but it can also result in health risks to you, your family and any pets you may have in the home.

As soon as you notice there is a problem, you should take action immediately. Do not wait until the heat becomes unbearable. When in doubt, always contact an professional for an HVAC service call.

There are several reasons that can cause your HVAC unit to stop the circulation of cold air. Some are simple and can be taken care of immediately, while others require the help of an expert.

Here are some things to look for with your AC not blowing cold air and how to fix the issue.

How Does a Central AC System Work?

In order to better understand what may cause your AC to not work properly, it will help to know how it works.

Your air conditioning unit uses a liquid refrigerant. This liquid passes over the indoor evaporator coils to absorb the heat inside your home. Absorbing the heat transforms this liquid into an icy gas. The AC unit’s fan blows across those refrigerant-cooled coils and pushes cold air through the duct work out to circulate into the home.

The gas-form of the refrigerant carries the heat back to the outdoor condensing unit where it transforms into a liquid after releasing the heat to the outdoor air.  This cycle repeats over and over to cool your home. With so many steps, there are several things that can cause a problem.

Let’s take a look at the top 5.

1. Leaking or Low Refrigerant

The refrigerant, mostly commonly Puron or R410A, is the chemical that puts the whole process in motion.

If your central AC is not blowing cold air, the refrigerant may be the problem. The unit could be running low and need additional refrigerant added.

The most likely cause of this is a leak. A leak not only keeps the AC unit from cooling properly, but also it can cause other issues within the home. For example, when it isn’t cool enough, humidity levels can rise in your home making it feel hotter than it is inside.

If you suspect a refrigerant leak, you should contact an HVAC professional right away. Unless the leak is large, it can be tricky to diagnose and fix these properly.

2. The Filter Is Dirty or Clogged

Another common problem with AC units are filters that are dirty or clogged. All year long, these filters work overtime trapping hair, lint, dust, and pollen. It doesn’t take long for them to become full if they are not changed regularly.

When this happens, the air cannot flow correctly into the home and your AC unit may shut off because it can’t get enough air. Without the air conditioner working properly, the inside temperature soars. Left that way too long, clogged filters can also cause parts to wear out faster than they should. It can even affect the evaporator coil and condenser and create a much larger problem.

In addition to routine cleaning, the filters should be changed every three months. If you have indoor pets, you may need to change it more often.

You should be able to replace indoor air filters easily yourself.  However, if you are unsure of the correct filter to use, an AC technician can help.

3. There Is a Problem With the Evaporator Coil or Condenser

The filters mentioned above do their best to keep the coils clean and operating at peak performance, however, even the coils will wear out over time.

Because of the constant moisture, your indoor evaporator coil can be prone to problems with mildew and even mold. (UV lights can guard against this and keep your air cleaner.) Coils can also freeze up if the refrigerant is running low within the system.

Issues with the coils will cause major disruption within the air conditioning unit and should be seen by an HVAC professional as soon as possible.

The condenser can also wear out over time. When your air conditioner is not blowing cold air and no other reason is found, have this checked as well.

4. Blocked or Clogged Registers

Just like air filters that are clogged and restrict airflow, a blocked or clogged register (or vent) can do the same thing. A return air register takes air into the system, and supply vents blow conditioned air into the house. Clogs in either cause problems.

The ventilation system runs throughout the house and if something creates a blockage or a leak in the ductwork, it will affect the cooling. A tear or hole in the ductwork could mean your cold air may be leaking out of your attic. Rodents like mice or rats that take up residence in your attic can do a number on ductwork and create leaks that affect how your system cools.

When something is restricting air near the vent itself, only the room with that vent may feel warmer than the rest of the house. That is a good indication there may be a ventilation problem in the ducts that supply conditioned air around your home or office.

It is also worth noting that occasionally a vent will get closed by accident. If just one room if particularly warm, check to make sure the supply vent is fully open.

There will eventually come a time when your HVAC unit is costing more and more to repair. When that happens, it may be time to consider replacing your system.

5. AC Not Blowing Cold Air – Thermostat Issue

The thermostat is where all the action starts. The AC will not turn on until the air temperature in the room rises above the control setting. The first step is to make sure the thermostat setting has not been changed. Make sure it is set to auto or cool. Occasionally, a thermostat will be set to heat instead of cool, which causes the problem.

If it is set correctly and the AC is still not coming on, the fault may rest with the thermostat itself. It if takes batteries, check and replace if necessary. If that still does not resolve the problem, a call to an AC professional is in order.

Proper Maintenance Prevents AC Not Blowing Cold Air

As with any machine, your central air conditioning unit needs regular maintenance. Filters need to be changed and all other working components need to be examined by a professional.

The standard recommendation is to have an HVAC maintenance tune up twice a year. This should happen in the spring and the fall. The technician can check your HVAC system and make any tweaks or repairs necessary before the weather gets hot or cold.

This not only keeps your unit running efficiently, but it also helps reduce the risk of unexpected breakdowns and expensive problems down the road.

Beat the Heat With Expert HVAC Service

When the weather is hot, you definitely your air conditioner or heat pump to be running in tip-top shape. If you have the problem of your AC not blowing cold air, it will not take long for the inside of your home to be miserably hot.

There are many reasons that can cause this problem and they range from very easy to fix, to quite extensive. If you are not completely sure what the problem is, you owe it to yourself and your family to have an HVAC professional come and assess the situation.

Contact the friendly professionals at Terry’s A/C & Heating for an expert repair in the Richmond, Katy and Fulshear, Texas area. We are a Carrier Factory Authorized Dealer and service all makes and models of air conditioning equipment for residential and light commercial applications.

We also offer a scheduled maintenance plan to make taking care of your HVAC investment care-free.  For more information on how we can help get the cold air moving again in your home, please reach out to us. We would love to earn your business.