Why Is My Air Conditioner Running But Not Cooling The House?

It’s frustrating when your AC is not cooling your home. From simple to complex, there could be many reasons why is your air conditioner running but not cooling the house.

You are probably thinking about calling a professional. But before you do so, why not check those reasons yourself? You can always call the professional anytime you want!

I will talk about all those reasons explaining why is your AC not blowing cold air and share with you some troubleshooting tips.

Reasons Why Is Your AC Not Cooling

why is my air conditioner running but not cooling the house

Most of the time, there is an easy fix for this problem unless there is serious damage to the components of your AC.

If you can quickly figure out the reasons, you can fully enjoy the hot summer in no time. So, here are some reasons why it’s not cooling the house:

  1. Check The Basic: Windows, Doors, And Humidifier

Always start simple when you face such problems. If you have kids, double-check the windows and doors. Someone from your family may have opened a door or window and forgot to shut it.

So, even your AC is running just fine, you won’t feel the cool air much until you shut the opened window. Your AC can’t work efficiently unless every door and window is shut and sealed.

Also, your humidifier can hold the heat that may be responsible for the inefficient operation of the AC. Make sure it’s not adding humidity in your room you want to cool down.

  1. Incorrect Thermostat Settings

This is where you should look first if your house is not getting cool enough like it used to. The first thing you should notice is whether it is set to cool or not.

If it is set to cool but still it’s getting a little hotter in there, make sure the temperature setting is right. Kids love to play with such stuff!

You should switch it back to the cooling operation and wait for a while after the system kicks in. Notice carefully whether the cool air is blowing or not. If nothing more is wrong, it should solve the problem.

  1. Clogged Air Filter

Usually, there is an air filter in your air conditioning system to catch dust and airborne particles. Apart from keeping the indoor air clean, it keeps the inside components of the AC cleaner and helps the system run more efficiently.

So, you can guess what happens when the filter is clogged or faulty, right?AC air filter

Eventually, the air filter gets dirty and a dirty air filter can block the airflow of your AC which in turn will make your house warm.

A clogged air filter also prevents the AC from removing excess moisture.

If the filter becomes too much dirty, it can shut off the entire operation of the system too apart from making the system struggle more to cool off your home.

Your AC may not turn on if the air filter is clogged too.

Depending on the model and brand, it should be easy to locate the air filter. Usually, it’s around the air handler unit. To inspect the air filter, turn off the AC and remove the filter.

After inspection, if you find it dirty, clean or replace it. If the condition seems satisfactory and yet AC is not cooling, the filter is not the problem. The problem could be somewhere else.

You should be doing such an inspection every month to prevent this problem from happening again.

  1. Dirty Outdoor Unit (Condenser)

The outdoor unit of your AC expels the warm air or heat from your home. But if it is covered in debris or becomes dirty, it can’t push out the heat properly.

Luckily, if this is the case, there is an easy fix for that problem. First, get rid of the debris. Then get your garden hose to clean the fins of the condenser.

You CAN’T use the strong stream to clean the fins. That will damage the condenser fins severely.

  1. Blown Circuit Breaker

AC circuit breakerFor some reason, people tend to overlook this issue a lot. Usually, AC units have 2 circuit breakers: one for the indoor unit and another for the outdoor unit.

The indoor unit will keep blowing air but you will feel warm if the breaker for the outdoor unit is tripped.

Let’s imagine another scenario.

Let’s say you have two electrical systems for your fans and AC. So, your fans will still work but the AC won’t.

Do yourself a favor and check the breaker box and reset it if tripped. If it trips again, call a professional to check it; because it indicates you have a bigger electrical problem.

  1. Leak In Refrigerant

The refrigerant gas absorbs the heat from your home’s air and keeps the temperature lower. Over time, there will be lower refrigerants in your AC system.

The low refrigerant also indicates a leak in the system. If there is any ice buildup on the unit or warm air coming out of the AC vent – these are indications of leaks!

You have a serious leak in your AC system if you hear any hissing noise near the AC. When such a leak happens, your AC can’t keep your home cool.

Observing those signs, if you become confident about such leaks, you should contact a professional to examine your AC and repair it.

I am not recommending you to fix such leaks unless you are a professional in this field because wrong handling can damage your system further.

  1. Leaks In Ductwork

Leaky ducts are another reasons why it’s not cool inside your home despite the AC is running. Hot and unconditioned air can seep into the ducts when there is any leak.

So, when the AC is running, hot air will come out of the AC vents. This is where things get complicated. Because it’s very hard to detect such leaks as those ducts are normally hidden in the attic.

But you can observe some symptoms of such duct leaks. If your house becomes dusty suddenly, you are getting higher electricity bills, or your rooms are unusually hot, there may be leaks in your ductwork.

Of course, you can use metal tape or any other sealant to seal those duct leaks if you are handy enough. But I would recommend contacting a professional because it’s a difficult situation to tackle.

  1. Frozen Evaporator Coil

Every central air conditioning system has an evaporator coil in the indoor part. The warm air of your house passesAC Evaporator Coil through the evaporator coil. It removes the indoor humidity as well.

But if it’s frozen, it can’t perform its functions efficiently. But how do you know? Are there any signs?


If you notice any frost forming on the copper refrigerant tubing or if there is any excessive condensate drainage near the indoor unit, you have a frozen evaporator coil problem.

The bad news is you need an HVAC professional to fix this problem because it is hard to just access the coil, to begin with!

  1. Faulty Compressor

You don’t get a faulty compressor often but it happens sometimes and you keep wondering why is my AC running but not cooling!

The compressor is the core of your AC that is located in the outdoor unit and primarily responsible to keep your home cool.

It circulates the refrigerant to remove heat from your home and dump the hot air outside. Sometimes, the compressor can’t draw sufficient air due to the piles of leaves and debris.

People tend to hide it using various mechanisms to distract others from the rest of the landscape. Some people even install a small fence around the compressor.

If this is the condition you have, then I must ask you—is it overgrown by vines or something like this?

If so, remove everything. Never put anything on top of it. If it can’t pump the refrigerant well or suck enough air in due to such conditions, the outdoor AC compressor won’t run properly and your AC can’t cool your house.

This is the worst-case scenario that may happen to you because you can’t repair the compressor of your air conditioner. And this is the most expensive component of the AC!

So, there is no alternative to replacing the compressor unless you have a valid warranty from the manufacturer.

  1. Heat Pump Is Not Working

Instead of the condenser or outdoor unit, some air conditioners have heat pumps that look like the AC unit. It can warm-up or cool down your house too.

As the heat pump is usually outside the house, it is subject to dirt, dust, and other particles. So, just like the condenser unit, it is subject to frozen or clogged coil, leaks in the refrigerant, etc.

So, you should thoroughly check the air filter, thermostat settings, and other above-mentioned issues for your heat pump too.

  1. Wrong Capacity

Even the too small or too big AC unit could be the culprit! This may happen if you have recently done any remodeling. A too-small AC unit can’t cool a bigger room. It will be constantly running too.

Alternatively, a too big unit may also cause problems. If you notice short cycles, the unit is probably too big. Ideally, your AC should run for at least 20 to 30 minutes continuously in each cycle.

But if the unit is too big for the room, it will run only for a few minutes. So, it can’t suck out the humidity from the room and keep it cool.

  1. Wrong Installation

This is something you should check again for your brand-new AC system. If you have installed it yourself, there is a huge chance of installing it improperly. Sometimes, the contractor can miss a thing or two during the installation.

Check for leaks or any other problems. Fix the stuck AC relay. Just call your contractor and inform them that it’s not cooling enough. They should give you a free re-installation.

Now, watch this video to check more reasons why your unit is blowing cold air.

When To Call A HVAC Pro?

ac is not cooling

The above steps should pinpoint the problems of your AC not blowing cold air and if you take proper steps, your AC should be running and cooling the house.

But I again recommend fixing complex problems like the leaking refrigerant or faulty compressor unit. If your AC system is too old like 10+ years old, you may need to replace the compressor.

Only an HVAC professional can assess it correctly. Sometimes, you may need to replace the entire system. So, make sure to call a professional before you make such a decision yourself.

Frequently Asked Questions (FAQs)

Why is my air conditioner not cooling my house below 80 degrees?

Answer: There could be many reasons why it’s not cooling below 80 degrees like blocked condenser, the leak in refrigerant, dirty air filter, etc.

How long does it take for AC to drop 1 degree?

Answer: Well, it depends on how many rooms and space we are talking about along with the capacity of the AC. It completely depends on the cooling power of the AC. However, a function central AC should cool a 4-bedroom house within 3 hours.

What is the reason for the air conditioner running continuously but with no cooling effect?

Answer: It happens when you have a dirty air filter and condenser coils. When those get dirty, they trap the heat and restrict the airflow.

Do air conditioning units have a reset button?

Answer: Yes, there is a reset button in almost every AC.

Where is the reset button on the air conditioning unit?

Answer: You can find the reset button in the outdoor unit of the AC system. Usually, it’s a red color button and should clearly indicate that it’s a reset button.

What to do if AC is running but not cooling?

Answer: Clean the dirty air filter and condenser. Fix any leaks in the ductworks and refrigerant. Check the electrical wiring too.

Final Thoughts

After spending a lot of time checking and digging, I finally came to know why is my air conditioner running but not cooling the house. I don’t want you to spend those long hours.

I believe I have listed all the possible reasons why the AC is not cooling and relevant fixes. Keep your head cool and follow this article.

If you do find this article useful, please share it with your friends!

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