A ductless mini-split in the corner of a room below the ceiling

Ductless mini-splits have become an increasingly popular choice for home heating and cooling. These units excel at maintaining strict environmental control of singular rooms and small spaces. 

Despite their growing popularity, central heating and cooling still dominates the market. Providing the same, efficient temperature control to a whole home with a mini split is doable but takes some planning.

Ductless mini splits are a heat pump system. They use refrigerant to transfer heat from one area to another. This means the unit does not have to “create” heat like a traditional furnace does. 

If this sounds confusing, you’re not alone. We see a lot of questions and misconceptions about mini splits and heat pump technology.

Do Ductless Mini-Splits Come Pre Charged?

Yes. A mini split from the factory will come “pre charged” with refrigerant. However, the amount of gas in the system is measured for a certain amount of lineset. If you have to add more copper line to reach the indoor air handler, you will need to add gas to account for the additional line. This is best done by a licensed HVAC technician.

In most cases, the accompanying lineset will be sufficient and you will not need to add any additional refrigerant.

How Does A Heat Pump Work?

A technician adjucts the pressure on a refrigerant tank being used in a mini-split system

Heat pumps use refrigerant to transfer heat. A refrigerant is a fluid or a gas that absorbs heat. Simply put, a heat pump takes heat and moves it from one location to another.

On cooling mode, the system takes warm air from inside the home and moves it outside. This is how all AC systems work. If you go outside on a warm day and put your hand over the AC condenser fan, you’ll feel it blowing warm air. This is the system releasing the heat from inside the home.

While traditional AC systems can only provide cooling, heat pumps can work in reverse. On heating mode, the system finds warmth in the air outdoors and moves it inside. Even in subzero temperatures!

What Kind of Refrigerant Do Mini Splits Use? 

Mini split systems, along with all modern AC systems, currently use R410-A gas. 

410-A gas was introduced around 2010 when the phase-out of R22 began. 410-A has been proven to have less environmental impact. 

Though refrigerant should never be purposefully vented into the atmosphere, AC leaks do happen and are detrimental to the environment. Anything involving AC refrigerant should be handled by a licensed HVAC technician.

R22 was the main AC refrigerant before 410-A took over. R22 systems are still around but are quite old. The production and import of R22 gas was officially banned in the US as of January , 2020. Meaning, if you still rely on an old R-22 AC system, you won’t be able to get refrigerant for it if it starts to leak. However, the last of the R22 units are old enough that they likely require replacement at this point.

Refrigerant is an integral part of the functionality of mini split systems. It is how they are able to provide both heating and cooling within a singular system. While it is important for homeowners to know how these systems operate, it is also important to call an HVAC company for anything relating to refrigerant concerns.

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