What Do You Do If Your AC Stops Blowing Cold Air?

On a hot and sweaty day, the last thing you want to be contending with is a malfunctioning AC system that is not blowing cool air. There are many reasons why your AC may have stopped working, likewise there are ways of troubleshooting the issue.

Read on to learn more.

The air filter needs to be changed

the air filter needs to be changed

The air filter is responsible for straining the particles from the indoor air supply, however, it will eventually fill to capacity, and over time it will get dirty. For the unit to work properly, this filter needs to be cleaned or changed.

Whilst the manufacturer’s specifications will state how regularly the filter needs to be changed, generally, once every 2 months is recommended. A dirty air filter can also cause the evaporator coil to freeze over.

If you change the air filter but the unit still isn’t blowing out cold air, it may be a sign that the evaporator coil is dirty. In this instance, it is recommended that you contact a professional who will be able to clean this component for you.

Check the thermostat settings

check the thermostat settings

If your AC system is not blowing cold air, it may be because the thermostat settings are incorrectly set. When the thermostat is set to ‘on’ it will continue to function automatically even if the air isn’t being cooled. Setting the thermostat to ‘’auto’’ may resolve this issue.

Alternatively, it may not be set at your desired temperature. Try and turn the dial to the lowest setting as this should encourage it to function. It is also worth carrying out a quick inspection of the thermostat to check that all of the wires are connected.

Unblock the condenser

unblock the condenser

Your AC unit will struggle to function if dirt particles and debris are blocking the condenser. Not only will this put more pressure on the unit and make it work faster but it can also cause the components to wear out sooner than you would like.

Some people may be able to resolve this problem by removing the debris themselves, however, depending on the severity of the dirt build-up, you may need to contact a professional who will be able to clean it thoroughly.

Check to see whether the refrigerant levels are low

check to see whether the refrigerant levels are low

Low refrigerant levels may result in an ice build-up in an AC unit and this can cause it to stop blowing out cold air. The refrigerant absorbs the heat before cooling it off and dispersing it into your home.

Alternatively, your unit may be leaking refrigerant which will of course cause the levels to decrease over time.

Allowing the system to continue functioning can result in damage and costly repairs. If you suspect that a leak is the cause of the issue, you should contact a professional who will be able to offer their help to resolve the problem.

Dealing with cooling systems and chemicals yourself can be quite complex. Sometimes an ice build-up can be resolved by running the unit with only the fan on because the fan will help to melt the ice.

Inspect the compressor for damage

inspect for the compressor for damage

The compressor in your AC is responsible for moving the refrigerant from the outside unit to the inside unit. A damaged or faulty compressor may affect how the system functions. If the compressor is damaged, it will typically need to be replaced but this can be rather expensive.

It is worth asking a technician to inspect your system if you suspect this is the issue but aren’t entirely sure.

Unclog the drain

unclog the drain

As your AC removes moisture from the air, the water that it collects will then be drained through a hose or a pipe. Over time, the drain may become clogged up and this will slow the system down until it is eventually no longer able to function.

If the water is not drained properly, there is a risk of it damaging the unit and your home. There is a fairly simple solution to this problem. You can either clean the drainpipe but if this doesn’t prove successful you may need to replace it.

Check that it is connected to the power source properly

check that it is connected to the power source properly

There may be a simple explanation behind the malfunctioning of your AC and this may be that it isn’t connected to the power supply. To identify whether this is the issue, you will need to check all the fittings to make sure that they are plugged into the outlet.

If this doesn’t appear to be the issue, it may be because a fuse has blown.

Inspect the ducts to see if they are broken

inspect the ducts to see if they are broken

The duct transports the clean air from the blower to the rooms inside your home. If the duct is torn or broken, the cold air may be escaping before it reaches the rooms. As such, this can make it feel as though your unit has stopped blowing in cool air.

To diagnose whether this is the issue check the other registers in your home. If the rest are blowing in cool air this pretty much confirms that the duct is at fault and needs to be replaced.

Depending on where the duct is located, you may be able to examine it yourself, otherwise, you will need to call a professional technician who will be able to check the duct for you.

These are some of the issues that may be affecting the functionality of your AC system.

Whilst some of these problems can be rectified by you, others will require the attention of an AC professional who will be able to inspect and identify the parts that are responsible for the lack of cool air before fixing or replacing them.

James Marshall

About the author

James is a business management professional and consultant with a former background in maintenance, repair, and hands-on projects. He enjoys DIY tasks and maintenance around the home as well as part-time writing. Read more »