How to Tell If Your Air Conditioner Is Low on Refrigerant

An air conditioner low on refrigerant will not be able to keep your home cool enough.  It might start by feeling like your air conditioner just can’t keep up with the heat. The temperature in your home may be rising by little or by a lot. When air conditioners aren’t cooling well or stop working altogether, the first cause people think of is maybe it is a refrigerant problem.

Refrigerant isn’t a renewable resource. When it’s operating they it is supposed to, it cycles back and forth absorbing the heat in the home, and carrying it out of the home. It operates like a train on a circular track. When properly charged, your air conditioner or heat pump recirculates the refrigerant around and around. In theory, you should never need more refrigerant, but sometimes extreme weather will throw us a curve ball.

Here’s what you need to know about an air conditioner that might be low on refrigerant. We will also cover why it is helpful to have an experienced, licensed air conditioning professional on the job.

Symptoms of an Air Conditioner Low on Refrigerant

Unless your leak is large with an audible hiss, it can take more than one visit to diagnose and fix refrigerant leaks. Sometimes dye is used to help diagnose pinhole leaks because they can be hard to spot. Extremely high temperatures can blow out piping joints that are welded together and cause leaks. Most commonly, this can happen in the evaporator coil indoors because it is the area that goes through the most volatile temperature changes.

As a homeowner, it can be tricky figuring out what is wrong until everything has just stopped working altogether. If you notice the temperature and humidity indoors ticking up little by little, sometimes you can catch it early and prevent a more expensive repair.

Here are some of the symptoms of an air conditioner with low refrigerant:

  1. Takes Your AC a Long Time to Cool Off

    If it takes longer and longer for your home to cool off, it could indicate a problem with refrigerant. Your indoor thermostat might be inching up in temperature and humidity for no explainable reason. Another classic symptom is if your air conditioner doesn’t cool well during the day, but catches up in the evening.

  2. Indoor Air Not Blowing Cool Enough

    If you hold your hand up to your air vents that blow in conditioned air, what is the temperature like? If it feels much warmer than it should, it can sometimes indicate a refrigerant problem. Keep in mind that it may not blow as cool when the temperature is 100 degrees outside.

  3. Frost or Ice on Copper Lines

    When refrigerant levels are not in balance, it can cause the refrigerant to become too cold and restrict airflow. Restricted airflow places tremendous strain on your air conditioner and can cause your evaporator coil to freeze up and stop working. Other causes of low airflow, such as dirty air filters, can cause a frozen indoor coil, too.

  4. Water Pooling Around the Furnace

    If your air conditioner has frozen up, it will eventually thaw out and the residual condensation will start dripping. We watch for the telltale signs of water pooling around the indoor furnace, which can sometimes indicate a problem with refrigerant.

  5. Listen for a Hissing or Bubbling Noise

    If you have a pretty big leak, you can sometimes hear a hissing or bubbling noise coming from the indoor evaporator coil or outdoor condensing unit. In this case, the temperature inside your home could go up and become uncomfortable very quickly.

    Every now and then, we come across an air conditioner that is completely empty of refrigerant because of something we call “blown points.” This is another term for a compressor failure. If your air conditioner’s compressor explodes because of an electrical failure, all of your refrigerant supply will be lost. The outdoor unit will expel oil and residual refrigerant along the bottom of the outdoor condenser. You could hear a loud hissing noise and see a white cloud if you are in the right place at the right time. It can be very dangerous to be around, so keep your distance. We recommend calling a professional to evaluate the situation.

  6. Short Cycling

    When your air conditioner tries to cool, but can’t,  it can get into a frustrating pattern called “short cycling.” Short cycling refers to an air conditioner that turns on and runs for a short time, then turns off. What happens is that your air conditioner never gets all the way through a true cooling cycle. When this happens, humidity levels may increase in your home if you live in an especially humid region like the Texas Gulf Coast and Richmond, Texas.

    When an air conditioner starts up, it removes much of the humidity which is why it starts to feel much cooler indoors as your air conditioner runs for longer periods. If your air conditioner, on the other hand, is turning on and off, it will have a hard time removing enough humidity to feel cool indoors.

    We aim for around 52-54% relative humidity indoors here in the Houston, Texas area. It might surprise you that Houston isn’t the most humid city in the nation, coming in at 89% annual average relative humidity, but it is pretty close.

  7. Electric Bills Higher

    If your electric bills are higher than usual for the time of year, it can indicate a problem with refrigerant. A higher electric bill is not typically the first symptom we look at. Electric bills during an especially hot summer are naturally going to cause higher utility bills. That doesn’t necessarily mean there is a refrigerant problem. However, higher utility bills do often accompany an ailing unit that is struggling to cool without enough refrigerant to make it work well. An air conditioner without enough refrigerant will continue to run as it tries to cool the home — running much longer than it would normally.

    ProTip: Make sure you look at your price per kilowatt hour on your utility bill because sometimes the price of electricity in Texas can change behind the scenes due to market conditions.

What Causes Refrigerant Leaks?

Some air conditioners never sprout refrigerant leaks. My sister’s 16-year-old system is edging toward the end of its life. It has never had a refrigerant leak. It has needed a new fan motor or run capacitor from time to time, but never a refrigerant leak. I mention that to show that a refrigerant leak isn’t a repair that is inevitable for every air conditioner.

Older air conditioning units and heat pumps are more susceptible to refrigerant leaks than newer equipment. The effects of normal operations and corrosion do affect air conditioners adversely, which is why air conditioning equipment has a useful life of about 10-15 years on average. You can increase an air conditioner’s life with regular maintenance.

Other more common causes of refrigerant leaks:

  • Leaky rubber seal around the air conditioning service valve
  • Loose assembly joints on the outdoor unit
  • Lack of service caps being replaced after service
  • Corrosion of the copper lines – The technical term for this is formicary corrosion, which refers to corrosion and pinhole leaks caused by exposure to formaldehyde and formic acid. Both substances are found in building materials and are common at low levels in most indoor air.
  • Puncture in the refrigerant line – Remodeling and lawn care are the usual culprits for this type of accidental damage.
  • Vibration from improper HVAC unit installation – If the system is not anchored and installed correctly, powerful motors can loosen or break joints causing leaks.

Most of the refrigerant leaks we find are located in the evaporator coil indoors because this is where the coil undergoes the most volatile temperature changes.

How Low Refrigerant Is Diagnosed

An experienced HVAC professional will ask homeowners some questions about how their air conditioner may be acting. It is very important to share as much as you can to make diagnosis easier.

  • HVAC professionals will bring gauges so they can look at the pressure inside your air conditioner. This can yield important clues as to what may be causing the malfunction. Specialized gauges are attached to the outdoor condensing unit to evaluate the pressure and the refrigerant charge.
  • If the leak can’t be spotted by listening for a telltale hiss, dye may need to be added to the system. This is very helpful to locate tiny leaks.
  • An HVAC technician will evacuate the system, which means they will safely remove all the refrigerant from the system, so it cannot escape into the air.
  • Then they will find and fix the leak.
  • They will test the fix.
  • After that, they will refill your air conditioner with the right amount of refrigerant to factory specifications.

These are the types of repairs that should be left to the professionals. Refrigerants in use today are regulated by the EPA and are considered ozone-depleting substances. There are special procedures for working with refrigerants for safety and to preserve the environment. This is why it is never okay to let refrigerant vent into the atmosphere. An HVAC professional will hold a Section 608 certification from the Environmental Protection Agency to work with refrigerants.

Does Low Refrigerant Damage My Air Conditioner?

Low refrigerant causes comfort problems for everyone inside. It can also have repercussions that affect your larger system. If your system has been struggling with low refrigerant for some time, it can wear out parts earlier than they should. In an extreme case, it can cause damage to the compressor which acts as an engine, driving the refrigeration process. As the compressor works harder to compress the air, it can damage the motor. When refrigerant is out of balance, it can cause the evaporator coil to freeze up altogether.

Government regulations require refrigerant leak repair. Refrigerant dissipating into the air has environmental and health repercussions. This is why if a leak is found, it must be fixed.

The other reasons you want it to be fixed in a timely way is that 1. refrigerant is expensive and 2. only balanced refrigerant levels are going to result in a comfortable temperature indoors.

Watch Out for These Refrigerant Boo-boos

Topping off a system with refrigerant without locating the refrigerant leak is never an appropriate strategy. If an AC technician recommends that to you, that should be your cue to start asking a lot more questions.  Too much refrigerant in your air conditioner is a recipe for disaster.

Installing a bigger air conditioner is also never the solution. You need one that fits your home or office’s specific heat load.

If your HVAC technician is not familiar with the EPA’s Section 608 Technician Certification, it could mean they do not have adequate experience to skillfully make this repair.

Let Us Help You Stay Cool

Refrigerant leaks that deplete your air conditioner can be particularly troublesome on a hot day. Contact Summer Terry at Terry’s A/C & Heating, headquartered in Richmond, Texas, and serving Fort Bend County and Southwest Houston. We can help you with an expert diagnosis and get your air conditioner or heat pump back up and running quickly.  If you are curious, you can learn more about refrigerants and your air conditioner. We feel that homeowners should know more about their HVAC investment, so they have the information they need to keep their air conditioning system working now and long into the future.

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