Updated: January 2024

Ductless mini splits are convenient to use and great at their job. They’re able to heat homes in the winter and cool them in the summer. Their versatility and relative efficiency are both reasons why they’ve become popular in recent years. In order to work effectively, these mini splits require coolant. Coolant allows the transfer of heat. Therefore, if you’re running low on coolant, heat cannot be moved very well from one place to another. You’ll probably notice issues pretty quickly, especially on a hot day. The interior temperatures will likely rise, even though it may seem like the system is running properly. A similar situation would arise in the winter, as your home would probably get uncomfortably cold when the exterior temperatures drop.

The Role of Coolant in a Mini Split

It’s important to review what exactly a ductless mini split is before discussing the importance of coolant. A mini split consists of two main parts. There’s an interior unit and an exterior unit, and they’re connected to each other through a conduit. The conduit consists of a drain, tubing and a power cable. The interior unit can be placed in a particular area of the home, such as a bedroom or living room, and it’s not connected to any ductwork.

During the summer, heat gets absorbed from the indoor air. By removing heat from the air, the system is essentially cooling it. The heat then gets sent through the mini split system to the outdoor unit. Here, the heat is expelled into the outdoor air. The cycle continues as long as the mini split is on and set to air conditioning mode. In the winter, the reverse process occurs to bring heat into the home.

How is the heat actually transferred? This is where coolant comes into play. Coolant is a substance that’s commonly used to regulate the temperatures of various systems. It can be in cold liquid form or a hot gaseous form. (Note that refrigerant is a type of coolant, so you may sometimes hear people using either term. When discussing a mini split, these terms can be considered interchangeable.)

Now that we’ve covered the basics, let’s get into the details. When the mini split has been turned on to function as an air conditioner, liquid coolant gets sent to the indoor unit. At the same time, the air handler brings in warm air from the room. The heat from that air gets blown over coils that house the coolant. Heat is removed from the air, and the coolant turns from a liquid to a gas. As it does so, it moves through the conduit to the exterior unit. When the coolant has gone into the exterior unit, a compressor turns the coolant back into a liquid. Heat is released through this process. The liquid coolant gets sent back through the system to the interior unit, where the process can start once again.

When mini splits are used to heat homes, the process is basically the opposite. In this case, the coolant is in liquid form when it’s in the exterior unit. This allows it to absorb heat from the outdoors. As it gets hotter, it turns it into a gas, and then it travels through the conduit to the indoor unit. A blower moves air over the coils in the indoor unit that house the hot gas, and this warms the air. This process cools the coolant and turns it back into a liquid that’s sent back outside again. This process works even in the winter since the temperature of the coolant can be significantly below the temperature of the outside air. The temperature differential is what allows the heat to be absorbed by the coolant.

When you have a mini split system installed, it should have enough coolant to do its job well. Mini splits are designed with closed systems, so under ideal circumstances, they should never need more coolant.

Possible Issues

Coolant is an integral part of a mini split system, so without it, there can be no transfer of heat. Unfortunately, there can be leaks in the system. In this case, you might be losing a little bit of coolant every day. At first, your system may be able to compensate for the minor loss. A small amount of coolant might not emit too many odors or be very visible, especially if it happens in a place where you don’t usually spend too much time. However, the coolant loss could start to be significant at some point. This would start to affect your system, and it won’t be able to heat or cool very effectively. You’d still feel air coming out of the vent, but it just wouldn’t be that cool in the summer or warm in the winter.

As we just touched upon, a coolant may have a certain odor to it. Some have described it as almost sweet. If there is a leak, you might smell something distinct in a certain area. Also, it could be visible. If you’re noticing a problem with your system, it’s a good idea to look around and see if you can notice any leaks around the interior unit, conduit and exterior system. These leaks could be on the ground or on a wall. Another potential symptom is ice on your coils. Without enough coolant, the system might not be at the right temperature, and it could actually get too cold. As a result, there could be some ice on the coils.

mini split

Keep in mind that a coolant leak can pose a danger. Coolant can be harmful to the environment and to your health, so it’s a good idea to get any type of leak taken care of as soon as possible. An HVAC technician would be able to identify a leak using a variety of diagnostic tools. A physical inspection is an essential task, and there are other ways to pinpoint leaks using advanced technology. If corrosion has caused the leak, then the damaged areas can be replaced. In other situations, more work may need to be done to prevent further leaks from occurring.

An HVAC Company You Can Trust

If you live in the Santa Clarita area and require a mini split repair service, you can turn to Affordable Air & Heating. Our full-service HVAC company has been in the industry for more than 20 years. During that time, we’ve enjoyed meeting and helping so many people in our local community. We hold our employees to high standards and have ensured that they’ve received extensive training. You can rest assured that we’ll keep your interests in mind as we go about our service. You’ll also appreciate our straightforward pricing structure and our willingness to answer any questions. We install, repair and maintain ductless mini splits, heat pumps, traditional air conditioners and heating systems. We also have experience with humidifiers, dehumidifiers and systems designed to enhance indoor air quality. Many of our customers have taken advantage of our membership plans. For a one-time cost, you can have two inspections every year, standard air filter replacements and discounts on repairs and replacement parts.

Call Affordable Air & Heating for more information

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