Air Conditioner Gas [How to, Issues & Solutions]

Many components contribute to making an air conditioner work, but an air conditioner gas is a vital part of the cooling process. Learn more about it in this article.

air conditioner gas

Air Conditioner Gas Leak – What to Do

It may be a gas leak if you notice a chemical or odd smell when your air conditioner is running. And if you suspect a gas leak from the air conditioner, turn it off immediately. Open doors and windows to create better ventilation and call for professional assistance. Air conditioner gas leaks must be fixed by professionals, primarily because it may be challenging to detect the leaks’ source.

The primary reason for a gas leak in an air conditioner is the corrosion of the refrigerant lines. Over time, external elements such as cleaning agents, water, rain, and sunlight affect the pipes and weaken them. And once corrosion starts, the next part will be holes in the pipes through which the gas escapes. 

However, corrosion does not happen overnight; it usually takes some time before you see such results. In some cases, you may never have to deal with a gas leak in your air conditioner for the duration of owning the air conditioner. So, if you are dealing with a gas leak within a short time of owning a system, it is crucial to find out its cause.

An improper installation may also lead to a leak. Typically, the brand that manufactures the air conditioning system should have professional installers. Stores usually have installers on-hand to offer installation services. But sometimes, new owners may try to save money and use cheap services, which may mean less-than-ideal installations. Other times, professional installers make an error, which may lead to a leak, but it is rare.


There are a few ways to prevent quick corrosion on refrigerant lines that lead to gas leaks. One way is to protect the outdoor condensing unit from direct sunlight and other natural elements. Leaving the unit exposed to water and sun daily is not ideal, especially if the refrigerant lines are not made of copper. 

Instead, put the condensing unit in the shade. If that part of the house is in the open with no available shade around it, build one to accommodate the unit. During the cold months, cover the condenser if the air conditioner is not in use. Icy weather further wears the unit out and drives it closer to the end of its lifespan quicker than normal.

If you are purchasing a new air conditioning unit, choose one with copper refrigerant lines instead of aluminum. Units with aluminum refrigerant lines may be more affordable, but aluminum corrodes quicker than copper. It does not mean copper never corrodes but does so at a much slower rate.

Is the Gas in an Air Conditioner Dangerous?

The gas in an air conditioning system is dangerous in more ways than one. The dangers it poses are why you must not try to charge the system yourself unless you have the necessary training. Air conditioner gas is dangerous to human health and the health of other living things. It may also damage the air conditioner if left unchecked. These are some known dangers of an air conditioner gas leak.

Danger to Human Health

Most times, refrigerant leaks occur outside the house. In such a case, you may not immediately get the sense of danger because the smell of the gas eludes you. The outside air dissipates it before you can smell it. Therefore, you may have inhaled an unhealthy dose before detection. 

The same may be the case if the leak is from the indoor evaporator coil. Most refrigerant gases do not have a detectable smell. Before you detect it, there may already be too much gas in the room. So unless you know what refrigerant smells like, you may not be quick to detect it.

Air conditioner gas can cause nausea and severe headaches. Chlorofluorocarbons are quick to absorb heat, and if you are constantly exposed to them, you may develop frostbite. Short-term exposure to the gas can cause a reduction in your ability to coordinate, convulsions, cracked skin, and an increase in your heart rate. Long-term exposure can cause critical medical issues such as cataracts, inability to breathe well, unconsciousness, skin cancer, and even asphyxiation in some cases.

Danger to Other Living Things

Chlorofluorocarbons, or CFCs, which are the primary coolant in most air conditioners, are quick to evaporate into a gas form. They make the air unfit for breathing if they saturate it, especially for plants and animals. 

Also, the Earth quickly absorbs them, contaminating the water that way. If organisms that get their water from underground sources drink the contaminated water, it quickly deteriorates their health. However, this can only happen if a massive leak is not quickly caught or old air conditioning units with CFCs in them are improperly thrown out.

Danger to the Air Conditioner

Refrigerant is the reason your air conditioner produces cool air. So if there is a leak, there will be a reduction in the available coolant in the closed system. As a result, the compressor and other parts must work harder to produce cool air. This causes the compressor to weaken long before it reaches the end of its lifespan. The same is true for other components.

Moreover, a leaking air-conditioner increases the electricity bills, sometimes by as much as 20%. As the air conditioner prematurely wears out because of extra pressure, it also increases the amount you have to pay for electricity bills. Replacing the compressor in an air conditioner is cost-intensive, so it is more affordable to fix the leak as quickly as possible.

What Type of Gas Is Used in Air Conditioners?

The gas used in all air conditioning systems is called refrigerant. Some call it Freon, but it is a trademarked name for the gas that air conditioners use, only that it is popular. Refrigerant works as a coolant that absorbs the heat in the room air and leaves it cool. 

It goes through a complex process to achieve this result. However, an air conditioner never needs to be recharged or refilled with refrigerant; the gas runs through a closed system and is reprocessed. So, it never depletes unless there is a leak in the system.

Types of Air Conditioner Gases or Refrigerant

Over the years, several types of refrigerants have been used in air conditioning systems. Manufacturers regularly sought ways to improve the gas, especially when earlier types showed their potential to deplete the ozone layer and increase global warming.

Chlorofluorocarbons or CFCs

This type of refrigerant was the most commonly used in the past. It is also called Freon, the brand name Dupont gave to R-12 refrigerant. Older air conditioner models still use CFCs, but this refrigerant is no longer in production. It was discontinued in 1994 due to the damage it causes to the ozone layer and greenhouse gas emissions.

Hydrochlorofluorocarbons or HCFCs

This type came on the scene after CFCs were banned from use. R-22 refrigerant is the most common HCFC and is only a little better than CFCs because of the chlorine content. However, it does not reduce the refrigerant’s potential to deplete the ozone layer and harm the environment.

Hydrofluorocarbons or HFCs

Manufacturers made this refrigerant type to compensate for the deficiency in HCFCs. It contains no chlorine and does not deplete the ozone layer, although it may still slightly contribute to global warming. The commonest type is R-410A and is better than all the previous versions when it comes to energy efficiency and ozone layer depletion. Other common types of HFCs are R-32 and R-134A. The former is used in air conditioners, while the latter is commonly used in refrigerators today.


Hydrocarbons or HC are currently the best refrigerants on the market today. R-600A and R-290 are the most common types; they are friendly to the environment, do not deplete the ozone layer, and are halogen-free. In other words, they are least likely to contribute to global warming or damage the environment.

They are green refrigerants, and their energy efficiency level is high. But they are also highly flammable, seeing as they are hydrocarbons. However, manufacturers who use these types of refrigerants in appliances claim they take the best measures to ensure safety for users and the environment. Nevertheless, R-410A seems to have the best energy efficiency and provides better air quality, making it the best choice for reliability and comfort.

Air Conditioner Gas – How It Works

You must understand the movement of the gas in an air conditioner before getting a good picture of how it works. There are several steps to how the gas or refrigerant in an air conditioner works, and we will take them one by one.

The Refrigerant in the Compressor

The refrigerant is first in the compressor. The compressor moves it around the air conditioning system on its way to producing cool air. The compressor takes the gas and compresses it, forcing its molecules together. This means a reduction in the gas so a large amount can fit into a small space.

When the molecules fit into a smaller space, they collide against each other and cause a reaction where their kinetic energy converts to heat. As this process happens, the compressor exerts energy which converts to internal energy in the refrigerant, thereby increasing the refrigerant’s overall internal energy. Consequently, the temperature, enthalpy, and pressure also increase.

The Movement to the Condenser

The next step in the refrigerant’s movement is to the condenser. While in the condenser, the refrigerant needs an increase in its temperature above the surrounding temperature so that it can successfully transfer heat. The higher its temperature, the easier it is to dissipate heat. 

The increase in the temperature also increases the pressure and turns the refrigerant from gas to vapor. At this point, it has a high temperature and pressure, so it passes through the coils of the condenser, making them hot. The fan blows to reduce the heat and resulting energy, and as the heat is removed, the vapor condenses into a high-pressure liquid with low entropy and enthalpy.

Passage through the Expansion Valve

From the condenser, the high-pressure liquid flows to the expansion valve, where the valve meters its flow into the evaporator. As it passes the valve, the liquid partially turns to vapor as the valve adjusts to permit the flow. The refrigerant’s temperature and pressure drop as it expands in the valve before completely flowing into the evaporator.

In the Evaporator

The blower begins to blow warm room air into the air conditioning system as the refrigerant enters the evaporator coil. By this time, the refrigerant is cool, and the air from the room is usually warmer at this point. As the blower blows the warm air over the coil, it absorbs the heat from the air, leaving it cool. Now, the refrigerant becomes vapor once again and begins to exit the evaporator. The fan continues to blow the now-cool air through the vents into the room.

The refrigerant is now a vapor with low pressure. But there is a slight change in temperature because of the heat absorbed from the room air. It expels some heat when it changes completely to vapor from liquid and transfers the rest when it returns to the condenser.

How to Know If My Air Conditioner Is Leaking Gas

The following are a few ways to know if your air conditioner is leaking gas:

1. The Smell of Gas

It is not always easy to detect the smell of refrigerant leaking from your air conditioner. However, the gas has a slightly pungent odor, so you may pick the smell up if you pay attention. If the air conditioner has a reduced airflow or seems to have trouble functioning optimally, check the air fo odd smells. 

The problem usually lies in the fact that gas leaks usually stem from the outdoor condensing unit, making it difficult to detect leaks through the smell of gas. Let a professional HVAC technician inspect the unit to determine whether or not there is a gas leak if you have your suspicions.

2. Soapy Bubbles

If you suspect your air conditioner is leaking gas, use soapy water to detect pinpoint leaks. Mix a little soap in water and apply it to the refrigerant lines. If there is a leak at any point, you will soapy bubbles forming at those points. Carefully run this test because you may need to keep the air conditioner running to detect the leaks, and it is dangerous to use water on an electrical appliance while it is connected to electric power.

3. Stains on Refrigerant Pipes

Inspect the outdoor pipes that carry the gas from the compressor and condenser into the evaporator. The air conditioner may be leaking gas if you see oily stains on the pipes. And if there are small oil puddles close to the pipes or compressor, turn off the air conditioner and get professional help.

4. Get a Liquid Tracer

You will find different types of liquid tracers on the market fit for detecting gas leaks in an air conditioner. So, consider this method if you want a quick result in determining if you have an AC gas leak. There is usually a fluorescent dye that exposes invisible gas so you know the exact leak point. Speak with a professional if you want to use this method.

5. Humming Noise

Listen for a low hum coming from the expansion valve close to the thermostatic pipe. If there is a gas leak, the valve makes a low humming noise, but it is usually difficult to detect due to the background noise in a room. Therefore, create as much quiet as possible and listen for the noise. Call for professional help if you hear it.

6. Use a Flame Burner

There are several types of flame burners to use for the gas leak test; all you have to do is find a suitable one. Using a flame burner is an excellent way to detect a leak, but you must be careful while doing it because refrigerants can be flammable. The flame on the burner is usually green, so pass the burner along the refrigerant pipes. If the flame changes from green to greenish-blue, there is a leak.

It is always recommended that you turn off the air conditioner if you suspect a leak, and call the manufacturer to request service. You can also hire an independent HVAC technician for further assistance.

How to Fill an Air Conditioner Gas

A professional is in the best position to refill the gas in an air conditioner. Refrigerant is toxic and can lead to frostbite if you are exposed to it for an extended period. Therefore, contact the manufacturer or hire an independent technician if there is a need to recharge the air conditioner system.

However, if you want to refill it yourself at home, ensure you wear thick work gloves and safety goggles. You will also need an air conditioner manifold gauge set, refrigerant, and a vacuum pump. The refrigerant must be the type your air conditioner model already uses for the best results.

Step 1

Start by turning off the air conditioner. There are two lines on the air conditioning system’s outdoor unit. One is the discharge line, which is on the high side, and the other is the suction line, which is on the low side. 

You will find them behind the unit if it is a window or wall unit, the part that hangs outside the house. Locate the suction line, through which you refill the system with gas; it is usually cool if you touch it, unlike the warm discharge line.

Step 2

A single bolt is on the suction line; use a Torx hex key to loosen it. The screw is like a valve that keeps the refrigerant from flowing out or in until it is closed. It is crucial to loosen the screw if you must refill the system with gas.

Step 3

Next, locate the bolt on the left and remove it. Get the AC manifold gauge and connect its blue hose to the port from where you removed the bolt. The yellow hose on the gauge goes to the vacuum pump. It is crucial at this point to remove moisture from inside the compressor; moisture mixing with the gas makes it useless.

Step 4

Close all the valves of the manifold gauge and connect the yellow hose to the cylinder of refrigerant. The end of the yellow hose connected to the gauge should be slightly loose before you open the cylinder. When all is in place, open the refrigerant cylinder for a second and close it again. Doing this removes air from the pipes; the air escapes from the end of the hose. Afterward, tighten the hose.

Step 5

Open the manifold gauge’s low side knob for about three seconds and close it. Next, turn the air conditioner on and give the compressor time to kick into action. When it does, open the same knob on the manifold gauge’s low side and leave it open for about four seconds. 

Close it for two seconds and check the pressure point on the gauge. Repeat the process of opening and closing the knob until the pressure on the gauge indicates 70 psi. You can only refill the system with refrigerant in small amounts at a time because loading too much at once damages the compressor.

Step 6

After you get to the correct psi range on the pressure gauge, turn off the refrigerant cylinder and the manifold gauge. Loosen and remove the blue hose from the suction line and the yellow hose from the refrigerant cylinder.

If you fail to reach the required psi range, stop the process, turn off the air conditioner, and call for professional help. It is important to take this step to avoid damaging the compressor. Fixing or replacing a compressor is a cost-intensive job.

How Much Does It Cost to Refill Air Conditioner Gas?

The cost of recharging an air conditioner with refrigerant depends on the size of the unit, location, and chosen contractor. If the manufacturing brand does the job, it may expensive unless the appliance is still under warranty. In that case, the repair may be free or at a reduced price.

Typically, an HVAC technician may charge between $200 and $300. An R-22 air conditioner, which is usually larger than others, may cost about $600 or higher. The amount will depend on the type of air conditioning unit and its size. Also, the price may change if the technician has to find and fix the leaks before recharging.

Signs an Air Conditioner Is Leaking Gas

The common signs an air conditioner has a gas leak are:

  • Reduced cooling: the air conditioner becomes unable to produce cool air like before. It takes too long to cool a room and runs for longer in a bid to produce cool air. In some cases, it may blow only warm air as the fan alone functions.
  • Longer operating time: you may hear the compressor and fan running for extended periods, longer than usual. This is another sign the unit may be leaking gas because there is not enough for the cooling cycle, triggering the compressor to operate longer and harder than it should.
  • Increased humidity: another sign the unit is leaking gas is an increase in the humidity in a room. Typically, an air conditioner should dehumidify a room while running, but if you notice reduced cooling and high humidity all of a sudden, check for a leak along the cooling lines.
  • Ice accumulation on the evaporator coil: apart from dirt coating the coil and promoting freezing, a loss of refrigerant in the system can lead to ice formation. When the refrigerant level drops, the pressure increases and the evaporator coil begins to freeze. If the filter is clean and there is no dirt on the evaporator coil yet it is freezing, you may have a leak.
  • Noise: you may hear a noise like hissing or bubbling from the outdoor lines while the air conditioner is off. If you hear a loud hissing like gas, there is a significant leak that needs immediate attention.
  • A spike in electricity bills: a drop in the air conditioner’s capacity ot cool leads to the compressor running for longer periods and this translates to high electricity bills. If nothing else alerts you to a leak, check the next bills for a noticeable spike.

Effects of Air Conditioning Gases on Global Warming

The first types of gases used in air conditioners as coolants had a negative effect on the atmosphere. While they were effective, the long-term effect on the ozone layer and living organisms was not worth the risk. 

When released into the atmosphere, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs) created holes in the ozone layer, speeding up the rate of global warming. CFCs did the most harm to the atmosphere and manufacturers and health institutions worked hard to find the best coolants for air conditioners without causing undue damage to the environment. 

These days, hydrocarbons are used in air conditioners because they are not harmful to the ozone layer and are green. Not every air conditioner manufacturer has switched to using them, so there are still some effects on global warming from air conditioner gases, although it is minimal.

Types of Air Conditioning Gas in Cars

There are three main types of refrigerants used in car air conditioners: R-134A, R-12, and R-1234YF.

The first type for most auto mechanics is R-134A, which some call HFC-134A. This type of refrigerant is commonly used in cars made after 1994 and before 2014 and is popular because of its efficiency, low flammability, and easy access. However, the gas is no longer manufactured because of the damage it causes to the ozone layer.

R-12 is another car air conditioner gas, although it is one of the oldest on the market. Popularly known as Freon, it was phased out due to the significant damage to the ozone layer. It is no longer in production, so it is usually difficult to find. Cars manufactured before 1995 use R-12 refrigerant but many have become retrofitted to use R-134A refrigerant for easier access and less environmental damage.

R-1234YF is the newest type of car air conditioning refrigerant. It is more ozone layer-friendly and cars manufactured from 2014 until today use it. Check with your local auto mechanic for the exact refrigerant your car uses and whether or not it is accessible.

Is It Illegal to Add Freon to a Leaking Air Conditioner?

It is illegal to add Freon to a leaking air conditioner. The Environmental Protection Agency (EPA) has banned the use of refrigerants with ozone-depleting properties from being used in air conditioners and refrigerators, and Freon is one such type of refrigerant. It is advised to use the services of an EPA-certified technician if you have a need to refill the refrigerant in your air conditioner.

How to Fix an Air Conditioner Gas Leak

An experienced technician will fix a gas leak in an air conditioner in two ways. One is to patch it and two is to replace the leaking coil or change the refrigerant line. They use the first method if the leak is small and can still be managed. 

However, if the leak is extensive, the only repair is to replace the coil or the cooling lines. The last resort is to replace the entire air conditioning system. Let an HVAC technician assess the damage and recommend the next step, but ensure a professional technician checks the leak and repairs it, especially if you do not have the skill set.

Refrigerant does not usually deplete from an air conditioning system. The gas is added to the closed system at the manufacturing level and it circulates the system as a coolant. Therefore, there is no need to refill the system because the gas lasts as long as the unit, which is about ten to fifteen years. The only reason there may be a need for recharging is if the closed system leaks.

How to Check Air Conditioner Gas in Car

To check the air conditioner gas in your car, you need a thermometer and gauges. Much like a house air conditioner, a car air conditioner has a low side port and a high side port. One is the low-pressure service port while the other is the high-pressure service port. 

The low-pressure port should be between the compressor and accumulator, on the firewall’s passenger side. The high-pressure port should be between the evaporator and condenser. Consult the user manual for the exact location of the ports if you do not find them in these locations.

Attach the air conditioner gauges to the service ports. Next, start the car and turn on the air conditioner, setting it to the maximum point. Select recirculation air if your car’s system has a button for recirculation air. Insert a thermometer into the air conditioner vent on the center of the dashboard. Then, give the compressor and pressures time to cycle and stabilize.

The reading you get for the gas will depend on the external temperature. If the temperature is higher than the temperature inside the car, you will get a higher reading on the gauge than if the temperature is lower. The pressure reading on the low-pressure side should be between 25 and 45 psi, while the high-pressure side should read between 250 and 400 psi., fluctuating with the external temperature.

If the pressure readings are lower on both service ports, it means the refrigerant level is also low. But check the reading on the thermometer; if the reading is 40 degrees Fahrenheit or is lower than the external temperature, the refrigerant level is normal. Otherwise, you may need to recharge the system.

How to Check an Air Conditioner Gas Pressure

As with a car air conditioner, locate the pressure gauges, that is, the low-pressure and high-pressure gauges. If these pressure gauges are not available on your specific model, you can use the discharge and suction lines to check the pressure.

Connect the manifold valve to the suction line; ensure the blue hose connects to the line. The pressure reading should be between 60 and 75 psi, depending on the size of the air conditioner. You can check the user manual for the value to expect for your specific air conditioner size. However, it is crucial that you allow a professional technician to perform this test, especially because refrigerant can be dangerous if handled wrongly.

Will Air Conditioner Work Without Gas?

Your air conditioner can work with a little amount of gas or refrigerant. But it is not advisable to operate the system on a low charge because it puts a lot of strain on the compressor and may damage it. 

Replacing the compressor is usually cost-intensive, the same as replacing the entire air conditioning system. Besides, the refrigerant level should not drop; there is a leak in the closed system if it does. So, hire a professional to check the system and recommend a permanent solution.

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