Everything You Need to Know About An HVAC Refrigerant

HVAC Refrigerant

Everything You Need to Know About An HVAC Refrigerant

Like most household products, air conditioners require power and electricity to function effectively. However, other parts and components are equally crucial in making an aircon cool in any given room. The refrigerant is one of these essential components. It's a liquid or gaseous chemical that absorbs heat and quickly supplies cooling to the air conditioning machine and its other primary sections, 

You may have noticed the AC refrigerant mentioned in conjunction with an aircon gas top-up, as most aircon service companies always recommend the latter after every aircon cleaning. Although it may appear to be an afterthought, the air conditioning refrigerant is critical for any air conditioning system. There'd be no refrigeration, air conditioning, or freezing technology.

This post will examine how an AC refrigerant works in an air conditioning system and the various types.



Step 1: Compressor

Let's look at how a refrigerant moves around the system to understand better how it works. The air conditioner compressor, sometimes known as the heart of an air conditioning system, drives refrigerant around all of the refrigeration system's components. The refrigerant will then enter the system as a saturated vapour in the form of a low-temperature, low-pressure gas. The compressor then draws in, which causes it to rapidly compress and force the molecules together, resulting in the same amount of molecules fitting into a smaller volume.

These molecules are all moving around because they have been compressed into a smaller space. It causes them to collide and interact more. Then, it will simultaneously turn the compressor's energy into internal energy within the refrigerant. It will transform their kinetic energy into heat once this reaction occurs. The refrigerant's internal energy increases as a result of this. Enthalpy, temperature, and even pressure rise as well.

Step 2: Condenser

The refrigerant then enters the condenser as a vapour heated to high pressure and temperature before passing through the tubes. The refrigerant then travels to the condenser as the next stage. Its temperature must be higher than the surrounding ambient atmosphere when it enters the condenser. This is to transfer heat successfully. As a result, the bigger the temperature differential, the more probable and simple it is for heat to flow.

The fans will start blowing across the condenser to remove any unwanted energy. The heat connecting the refrigerant eliminates when the air passes through these tubes. It removes heat from the system, it condenses into a high-pressure liquid with lower enthalpy and entropy.

Step 3: Expansion Valve

The expansion valve begins measuring the refrigerant flow into the evaporator once the refrigerant enters it. You will also need to adjust the valve to allow some passage to the refrigerant, which is now a mixture of liquid and vapour. The valve will function by filling in the void once it has passed through. With this expansion, the refrigerant's pressure and temperature drop even more. After that, it passes through the expansion valve and into the evaporator.

Step 4: Evaporator

Once the refrigerant has made its way into the evaporator, it goes through a fan. It blows warm air from the room across the coil. Because the room air temperature is higher than the temperature of the cool refrigerant, it can absorb more energy and boil fully into vapour.

Step 5: Refrigerant Vapour

The refrigerant's low temperature barely changes when it leaves the evaporator as a low-pressure vapour. The fact that it does not increase exponentially is due to a phase transition from liquid to vapour. When the fluid is no longer in this phase, the temperature will change.



Now that you understand how a refrigerant works in an air conditioning system let's look at the several popular refrigerants used.

Chlorofluorocarbons (CFCs) and R12

CFCs were an older and now-defunct form of refrigerant. Because this refrigerant widely connects with helping the greenhouse effect and global warming, manufacturers decide to phase it out in 1994.

Hydrochlorofluorocarbons (HCFCs) and R22

Despite being less harmful than CFCs and R12, the EPA has mandated that the R22 be phased down by the Clean Air Act of 2010. By 2020, this type is likely to be phased out.

Hydrofluorocarbons (HFCs), R410A and R134

R410A and R134 are safer for the environment than the preceding varieties because they do not include chlorine. They're also being used instead of R22. Air conditioning units that employ them are more efficient, reliable, and capable of delivering superior cooling, air quality, and comfort.


Copper coils in air conditioners hold refrigerant. The refrigerant changes from a low-pressure gas to a high-pressure liquid as it absorbs heat from the indoor air. The refrigerant goes outside by air conditioning components, where a fan blasts hot air on the coils and exhausts the external part.

After that, the refrigerant cools down and reverts to a low-pressure gas. Another fan blasts air over the cool coils inside the house, distributing the generated cold air throughout the structure. The cycle then repeats itself.


A refrigerant can theoretically last indefinitely. A unit doesn't consume it in the same way that fuel is. When an air conditioner is in good working order, the refrigerant continuously recycles within a closed system to keep your home cool.

On the other hand, the AC tubing tends to create leaks in the system as it ages and wears out. What's the result? The refrigerant level in your aircon unit will begin to decline.



Refrigerant isn't a fuel. Thus an air conditioner won't run out of it in most cases.

An air conditioner gets its energy from the home's electrical system, which serves as its "fuel" and source of electricity. On the other hand, refrigerant does not provide power to the air conditioner. It's what the air conditioner employs to transport heat energy from one location to another. The chemical combination that makes up refrigerant absorbs heat from within a house, cools it down, and then releases it to the outside through evaporation and condensation.

The key component is that the refrigerant is not consumed or dissipated throughout this procedure. For the entire life of the cooling system, it will remain at the same level, known as the air conditioner's charge.

The only exception is leaking along the copper refrigerant line or at connection points. It allows the refrigerant to leak, putting the entire air conditioner in peril. If you hear your air conditioner hissing, see frost on the indoor coil, or notice a decline in cooling power, it could signify refrigerant leaks.


If it's your first time dealing with an AC refrigerant leak, it's important to understand why they happen.

The refrigerant inside your air conditioner removes heat from the air pushed through it. The amount of refrigerant in your air conditioner remains constant throughout its life. You don't need to "top off" or replace it.

Reduced refrigerant levels can cause the problems mentioned above, but other dangers are also. The coils within an aircon have fractured in most cases, generating a gradual, continuous leak. On the other hand, other components could fail and cause a leak.

Failure to repair your air conditioner might result in long-term issues, such as:

  • Damages your aircon unit
  • Energy use has increased.
  • Harm the ozone layer of the atmosphere
  • Climate change

Low-refrigerant air conditioners will turn on and run more frequently and for longer periods. A leaky air conditioner can increase your energy expenses and increase your chances of receiving a high repair charge. So, what's causing the refrigerant leaks in your air conditioner? We will discuss three reasons below.

Wear and Tear

The wear and strain on your air conditioner might cause a refrigerant leak. Around the valve stems on the service valve are rubber seals that might wear out and leak over time. Outside, the system can corrode, causing the assembly joints to rot. These types of leakage are not visible during the first year, but they usually appear afterwards. In other circumstances, these leaks are rather straightforward to repair and require the services of a professional to replace a component. Other, more acute situations require more extensive repairs to remove rusty parts.

Pinhole Leak

A pinhole leak is another type of leak caused by "Formic,". It's a natural acid that will eat away at your copper tubing. Leaks like this usually don't surface until later in the game. When they do appear, they will be joined by more leaks in various sections of the system's components and copper tubes. It will need a costly replacement or repair. Formaldehyde produces Formic acid, which develops on the coils found in various home-building materials. If it builds upon the tubes, it can produce Formic acid and cause pinhole leaks in the copper tubes. Because metal does not rust, manufacturers are transitioning to all aluminium replacement coils.


If you're familiar with indoor air quality, you'll know that formaldehyde is a common pollutant in today's homes. On the AC coil in the house, formaldehyde can convert to formic acid. It is relatively mild. But over five years, it will cause pinholes in the copper tubes. It's called Formicary corrosion, so many contractors prefer to use R-22 by the skid. The interior air in most, if not all, homes contains some formaldehyde, which causes Formicary corrosion and refrigerant leaks.



The following symptoms can identify a refrigerant leak:

  • There is a puddle of liquid or traces of wetness near the unit.
  • Cooling that isn't as efficient.
  • Evaporator coils have ice buildup.
  • Indoor humidity levels are higher than usual.
  • Long periods of cooling (aircon stays on longer).
  • Bills for energy have increased.
  • Your air conditioner is making noticeable bubbling noises.

If there isn't an evident puddle of liquid and you're attempting to figure out if you leak, take a closer look at these frequent indications. If you're still unsure, hire a pro to evaluate it and make appropriate repairs or replacements.

Refrigerant and its derivatives, commonly found in older aircon equipment, are exceedingly dangerous to your health. Refrigerant and other chemicals can lead to burns and lung damage. If you suspect your air conditioner is leaking, we highly urge you to get professional help.


One of the most common problems with air conditioners is that the system loses refrigerant due to a small leak. Larger leaks in an air conditioning system are often easier to detect since they leave evidence such as an oil stain, a visible hole or fracture in a coil, and in some circumstances, the hissing sound of refrigerant escaping when trying to add refrigerant.

Larger refrigerant leaks will very certainly necessitate the replacement of the evaporator or condenser coils. If a larger leak causes your system to lose all of its refrigerants, it's necessary to be evacuated to remove moisture and other non-condensible. You can accomplish this by attaching a vacuum pump to the system, which removes any contaminants. It won't work properly even after recharging your system if you don't do this. When you discover a tiny leak in your system, the technician will often look for it. Then, he will add refrigerant to the air conditioner, only to leak it out again by the next cooling season. It can cost up to hundreds of dollars over a year or two. The other issue with simply adding refrigerant is that your energy expenses will be very high to run a not fully charged system before you know it.

A refrigerant leak repair kit, which includes the line, valve, and sealant, is a straightforward and cost-effective approach to treating tiny refrigerant leaks. Connect the bigger black or suction cable at the condenser or outside unit to the hose and access fitting, and turn on the air conditioner. It will suck the compressor into the system, sealing any small leaks throughout the system. Keep in mind that this product is primarily for home and commercial air conditioners with leaks that cause the charge to be lost for a year or more.


If the leak is in your AC coils, finding the cause of the leak can be difficult. A/C businesses usually use sophisticated technology to find the holes or cracks causing your leak.

This procedure necessitates a thorough understanding of your air conditioner and HVAC system. Self-performed, it frequently necessitates specialized equipment and may expose homeowners to hazardous chemicals. Professionals will be able to figure out what's causing the problem and perform the necessary repairs to get your AC system run again properly.

Your HVAC specialist will execute one of two common repairs, depending on the location and degree of the damage.

Patch the Cracked Coil

If the hole isn't too big, your expert will patch it up using a patch that can withstand the refrigerant liquid and prevent subsequent leaks.

Replace the Coil

If there are multiple holes in the coil, or if the coil shows symptoms of wear or contamination, your HVAC specialist will most likely suggest changing the entire coil. They'll find a replacement coil and finish the installation.



Your air conditioner should work correctly and keep your home cool and pleasant all summer long if you give it a yearly tune-up in the spring and change the filters regularly. Something is wrong if your vents are blowing warm or room-temperature air. It means you need to recharge your aircon.

When someone talks about recharging an air conditioner, they're referring to adding more refrigerant to the machine and making sure the refrigerant is correctly pressured within the system. You'll need to contact a professional heating and cooling specialist if you require refrigerant for your air conditioner; according to EPA laws, only a licensed professional can replenish your home's HVAC system.

How Often Do You Need to Recharge Your Air Conditioner?

Within A/C units, the refrigerant systems are sealed. Unless the refrigerant system develops a leak, residential air conditioners are not designed to require recharging. When you get your regular air conditioning tune-up, the technician will check to see if your unit's refrigerant levels and pressure are acceptable and whether the refrigerant system is leak-free. If the refrigerant system in your unit springs a link, you must repair the leak. Also, you must refill the refrigerant system.

When an air conditioner leaks refrigerant, it usually blows warm air. As the refrigerant in your unit leaks out, it will gradually get warmer, reducing the efficacy of your unit over weeks or months. Because the refrigerant is no longer present, the air travelling through your device is no longer cooled. However, it won't go from cool to warm overnight, as it might with a malfunctioning thermostat.

The accumulation of ice or frost in or on the unit is another symptom of leaking your refrigerant. The refrigerant gas freezes everything it comes into contact with, which is how it cools outside air before pumping it inside your home. It's usual to notice some frosty-looking coiled pipes inside your unit. These are the condenser coils, an important component of the refrigerant system. If everything appears to be frozen, or you notice frost on the outside, it could be due to a leak.


If you're concerned that your car's air conditioning isn't blowing cold air, check the refrigerant level.

Refrigerant leaks in your car A/C can cause your car to overheat, so regularly checking refrigerant in your vehicle is recommended for a car owner. As a result, you should be aware of the presence of refrigerant in your car.

When checking refrigerants in an automobile, basic safety precautions are usually recommended. You'll need air conditioning gauges and a thermometer to check the refrigerant in your car. A quick inspection surrounding your car's air conditioning will assist you in correctly checking the AC pressure in your vehicle.

Appropriate instruments are always the most helpful when checking the Freon level in your car. Here are the tools you'll need to check your car's refrigerant level.

  • A/C Gauges
  • Thermometer
  • Safety Goggles


1. Connect the gauge to the service ports.

To check Freon in the car, you must connect the gauges to the service ports. Low-side service ports are sometimes known as low-pressure service ports. The low-pressure and high-pressure service ports are both found on every vehicle.

The low-pressure or low-side service port will be between the accumulator (placed on the passenger side of the firewall) and the compressor.

On the other hand, the high pressure is on the line connecting the condenser and evaporator on the firewall.

2. Set the A/C unit to its maximum setting.

Start your car's engine first, then turn the air conditioning to the maximum setting. Air conditioning controllers come in a variety of shapes and sizes.

Select recirculation air if your car's air conditioning system has a switch or button.

After that, place the thermometer in the dash's central air conditioning vent. You connected the gauges to the service port and inserted the thermometer into your car's centre A/C vent.

3. Allow a couple of minutes for the compressor to cycle and the pressures to settle before taking the Freon reading.

Remember that the low-pressure service port on a typical system will read anywhere from 25 to 45 psi. The outside temperature affects the service port score.

The high-pressure service port side will have a pressure range of 250 to 400 psi. You're probably aware that this is dependent on the ambient temperature. When the outside temperature is higher, the gauge reading is higher.

If the readings on both sides are less than this, the refrigerant level is low. Take a look at the thermometer to see what the temperature is.

Indicate normal system function if the temperature is 40 degrees Fahrenheit or lower than the outside temperature.


Aside from the expense of freon, homeowners must also factor in the cost of labour.

Freon costs between $125 and $150 per pound. Additional labour costs will range from $70 to $100 per hour. Depending on the kind and size of their HVAC unit, most homeowners will pay between $200 and $400 for a refill. You may need to invest $600 or more if you have a larger r22 unit. To put it another way, a 25 pound r410A unit can cost anywhere from $100 to $175.


It leads us to our final question. Is hiring an HVAC specialist for a Freon recharge worth it? Yes, it is correct. While recharging your aircon may be a simple process, it requires skill and knowledge. In fact, under EPA section 608 of the Clean Air Act, everyone who buys or handles refrigerants for air conditioning must have a license. Recharging with the incorrect coolant can cause your machine to fail and necessitate a replacement. It's in your best interest to contact an expert technician to get the job done right, whether you need a recharge to top up your unit since it's undercharged or you suspect a leak.

HVAC Shop Automotive Charging and Recovery Stations

During recharging and draining out the residual refrigerant to clean out the unit when changing to a fresh set of refrigerant, Automotive Charging and Recovery Stations are essential equipment.