What Is a Mini Split Air Conditioner?

A mini split is a type of ductless air conditioning system. They are often known as split systems and are considered an alternative to central air or window units. Because of their small size, mini split systems typically are used in homes, but there also are some light commercial applications.


What Is a Mini Split Air Conditioner?

A mini split system is made up of two basic components: an indoor fan unit and an outdoor condenser. The two units are connected by a series of pipes or conduits, which contain refrigerant and condensate lines, as well as electricity to supply power to each unit. The indoor fan can be recessed or surface-mounted and can be installed in or on the walls or ceiling within the area that requires cooling.


Mini splits are primarily used to cool homes that are not equipped with central air conditioning. A single fan unit can cool one room, or multiple fans can be connected to one outdoor condenser to cool several areas. Split systems are also useful for cooling home additions. Rather than extending the duct network to the new room and possibly up-sizing the central air conditioning unit, a mini split can be installed to cool the new addition.


The installation process associated with these units is fairly simple, especially when compared with the complex process of installing central air. First, the outdoor unit is set onto a solid surface or installed on a new concrete pad. A 3-inch hole is drilled in the home's exterior wall to make room for condensate and refrigerant lines, then these lines are run inside the house to the fan unit. The fan unit can be installed anywhere in the home, up to 50 feet away from the condenser.


Mini split air conditioners offer a number of advantages over other air conditioning systems. They require no duct work, which keeps overall costs low. By using a mini split to cool a room, you can save the cost and messy demolition associated with adding ducts to your home. These units also offer a high level of energy efficiency by directing cool air only where it is needed, rather than into the entire house. Once installed, the mini split unit remains in place. By contrast, window units must be removed and stored in the winter or covered, which can lead to drafts and heat loss.


Still, mini split systems also have a numbers of drawbacks that you should consider. First, they are more expensive than other air conditioning systems, when comparing the cost per ton of cooling capacity. In small spaces, this might make sense, but in larger homes, it might be cheaper to install central air or window units. In addition, many homeowners might not be happy with the appearance of the fan units inside their homes. Finally, because these units are relatively new, it can be difficult to find qualified installers in some areas.

About the Author

Emily Beach works in the commercial construction industry in Maryland. She received her LEED accreditation from the U.S. Green Building Council in 2008 and is in the process of working towards an Architectural Hardware Consultant certification from the Door and Hardware Institute. She received a bachelor's degree in economics and management from Goucher College in Towson, Maryland.