Air Conditioner Not Blowing Cold Air: Causes and Fixes

Woman cooling herself down with an ice pack on her head

There’s nothing worse than coming home on a scorching day to find your air conditioner not blowing cold air. It’s a frustrating situation that can quickly turn your home into an oven. Why is your AC not blowing cold air, and how can you fix it?

Let's explore why your AC stopped blowing cold air and how to get your system back in working order as soon as possible.

Why Your AC Might Not Be Blowing Cold Air

An air conditioner is a complex system, and several issues could prevent it from cooling your home effectively. What causes this type of air conditioner problem, and what can you do about it? Here are the most common reasons why your AC might not be blowing cold air:

1. Dirty air filters

Air filters trap dust, pollen, and other airborne particles in order to keep your indoor air clean. They also help protect the internal components of your AC system. These filters can gradually become clogged with debris, reducing airflow. When airflow is restricted, your system struggles to cool your home efficiently. Dirty filters can also contribute to frozen coils, further compromising the cooling process. Replacing your air filter regularly—at least every 1-3 months during heavy usage—can prevent these issues and improve overall system performance.

2. Refrigerant leaks

A consistent amount of circulating refrigerant is required for an air conditioner to run properly. Your air conditioner absorbs heat from inside your home and releases it outside. If there’s a leak, your refrigerant will be depleted. This not only leads to warm air blowing through the vents but can also strain the compressor, potentially leading to costly repairs. You might notice a hissing sound near the unit or see ice forming on the refrigerant lines. Since refrigerant is hazardous, it’s essential to leave this repair to certified HVAC professionals.

3. Thermostat problems

Your thermostat acts as the control centre for your AC system. If it’s not set correctly or isn’t functioning properly, it can lead to cooling problems. For instance, if the thermostat is set to “heat” instead of “cool” or the temperature setting is too high, the AC won’t blow cold air. Additionally, older or malfunctioning thermostats may send incorrect signals to the system, causing it to run inefficiently. Consider checking the thermostat’s settings or replacing it with a programmable or smart thermostat for better control.

4. Frozen AC units

Warm air often comes from your air conditioner when the evaporator coils are frozen. Coils usually freeze due to dirty air filters, blocked condensate lines or drains, broken fans, or refrigerant leaks. If any of these occur, it sets off a chain of events. First, condensation may build up on the evaporator coils. Then, it freezes and the coils are unable to absorb heat. This can cause water to form around the unit, leading to further damage in your home. A subsequent breakdown of the compressor could occur, requiring costly repairs. If you suspect your air conditioner is frozen, contact your local Aire Serv^® for professional services.

5. Blown breakers

Air conditioning systems need a significant amount of power to operate. If there’s an electrical overload or the unit is overworked, it can trip the breaker, cutting off power to the system.

If your system doesn't receive regular maintenance (generally once a year), dirt can accumulate on the evaporator coils, resulting in frozen coils or an overworked machine. When an air conditioner pulls more power, heat increases in the unit, and this can trip the breaker.

Changing the air filter regularly in combination with regular service from a certified HVAC professional can prevent a blown breaker and frozen coils. If you believe your breaker has blown or been tripped due to an overactive air conditioner, contact Aire Serv for a professional tune-up.

Quick Troubleshooting Tips to Try First

If your air conditioner has stopped blowing cold air, here are a few easy steps to try before calling an HVAC professional:

Check Your Thermostat Settings

The thermostat should be set to “cool” and the desired temperature should be lower than it currently is in the room.

Inspect Air Vents

Blocked or closed vents can restrict airflow and reduce cooling. Ensure all vents are open and unobstructed.

Replace the Air Filter

A dirty filter can hinder airflow, making it harder for your AC to cool your home. Replace filters regularly to prevent this.

Look at the Outdoor Unit

Check for dirt, debris, or obstructions around the outdoor unit, as this can block airflow and reduce efficiency.

These simple fixes might solve your problem, but if your AC is still not blowing cold air, there may be deeper issues.

Simple Fixes for Common Cooling Problems

When your air conditioner stops blowing cold air, some problems can be resolved with simple troubleshooting before calling in a professional. Here are a few common issues and practical steps to address them:

Clogged or Dirty Air Filters

Dirty air filters can restrict airflow, making it difficult for your AC to cool efficiently. To fix this:

Locate the air filter in your HVAC system, usually near the return air duct or inside the air handler.
Remove the filter and inspect it for dirt and debris. If it looks dirty or clogged, replace it with a clean one.
Check your system's manual to ensure you’re using the correct type and size of filter.

Regularly replacing filters every 1-3 months can prevent this issue and improve system performance.

Blocked or Closed Vents

Blocked or closed vents can limit airflow, causing uneven cooling or warm air. Here’s how to address this:

Walk through your home and check all vents to ensure they are open and unobstructed by furniture, curtains, or other objects.
Vacuum vents to remove dust and debris that might restrict airflow.
Avoid closing vents in unused rooms, as this can create pressure imbalances in the system.

Thermostat Settings

Incorrect thermostat settings can easily cause cooling problems. Double-check the following:

Ensure the thermostat is set to “cool” mode and the desired temperature is lower than the current room temperature.
Replace the thermostat batteries if they are low, as this could affect functionality.
If you have a programmable or smart thermostat, review the schedule settings to ensure they align with your cooling needs.

Frozen Evaporator Coils

If you suspect frozen coils, you’ll need to take these steps to address the issue safely:

Turn off the AC and switch the thermostat fan to the “on” position to help thaw the coils.
Look for dirt in the air filter. Restricted airflow can cause freezing, so if the filter's dirty, replace it.
Inspect the area around the unit to ensure no obstructions are blocking airflow.

If ice continues to form, you may have a refrigerant leak or another issue requiring professional assistance.

Refrigerant Leaks

Refrigerant is essential for cooling, but leaks are best handled by professionals. However, you can identify potential leaks by:

Checking for ice buildup on the refrigerant lines or around the outdoor unit.
Listening for hissing sounds, which can indicate escaping refrigerant.
If you notice these signs, turn off the AC to prevent further damage and call a certified HVAC expert immediately.

Tripped Circuit Breakers

A tripped circuit breaker can leave your AC without power. Here’s what to do:

Locate your home’s breaker box and check if the AC circuit has tripped.
If it has, reset it by switching it off and then back on.
If the breaker trips again, do not reset it repeatedly, as this may indicate an electrical problem requiring professional attention.

While these steps can resolve many common cooling problems, some issues, such as refrigerant leaks or electrical malfunctions, require the expertise of an HVAC representative. If you’re unable to fix the problem or it persists, call a trusted professional to ensure your system is repaired safely and efficiently.

How to Keep Your AC Running Cold with Regular Maintenance

Routine maintenance can help you avoid most AC issues. Here are a few tips to keep your system running smoothly:

Replace Filters Regularly

Dirty filters can block airflow and reduce efficiency. Check and replace filters every 1-3 months, especially during peak usage.

Clean the Outdoor Unit

Remove dirt, leaves, and debris around the outdoor condenser unit to ensure proper airflow.

Schedule Annual Tune-Ups

Professional maintenance can catch potential problems early, keeping your AC in top shape.

Monitor Humidity Levels

Excess humidity can strain your system. Use a dehumidifier if needed to maintain optimal indoor conditions.

Knowing When It’s Time to Call a Pro

While some issues can be resolved with basic troubleshooting, others require expert attention. Here are signs it’s time to call a professional:

Your AC is blowing warm air consistently, even after basic troubleshooting.
There’s a noticeable refrigerant leak or frozen coils.
The unit frequently trips breakers or shuts off unexpectedly.
You haven’t had a professional tune-up in over a year.

Licensed professionals have the experience and tools to do the job right and get your system back online. If your air conditioner is not blowing cold air, don’t wait. Breathe easy with professional service from your local Aire Serv. If you’re wondering how to fix an AC not blowing cold air, the best option is to call a trusted professional. Call us or schedule an appointment online to get started.

Stay Cool: Final Thoughts on Fixing Your AC

An air conditioner not blowing cold air can make summer unbearable. Understanding the causes and solutions can make all the difference. Whether you’re dealing with a refrigerant leak, dirty filters, or frozen coils, addressing these issues promptly is essential to restore your AC’s cooling power.

Regular maintenance and professional tune-ups are key to preventing problems before they start. If you’re dealing with a stubborn cooling issue, don’t wait. Call your local Aire Serv or schedule an appointment online to breathe easy again.

Pro Tip: Want to lower your electricity use? Learn energy-saving tips from Mr. Appliance, another member of the Neighborly^® community of brands. Together, we help make home life easier and more efficient!

Home appliances, like air conditioners, can be power hogs. Learn how to limit your appliance electricity use with these tips from Mr. Appliance. Like Aire Serv, Mr. Appliance is a part of the Neighborly^® community of home services brands.

This article is intended for general guidance only and may not be applicable to every situation. You are responsible for determining the proper course of action for your property and your situation. Aire Serv is not responsible for any damages that occur as a result of any advice or guidance derived from blog content. For the most accurate guidance, contact an independently owned and operated Aire Serv for more information and a professional on-site assessment.