What Is a Split System in HVAC?

Split System: What Is It, How It Works, Types, Cost, and Size

A split system is an HVAC system used for heating, cooling, dehumidifying, and ventilation.

Split systems are one of the most popular HVAC systems because of their convenience and efficiency. While some split systems have only a cooling mode, or “straight cool”, reverse cycle split systems can do both heating and air conditioning. 

A split system is an HVAC system with two units: an indoor and outdoor unit. These units are connected through copper lines or tubing.

A split system’s main feature is the ability to install the condenser unit outside remotely. This configuration allows the split system to disperse the collected heat remotely from the air handler. This is optimal because the air handler’s most efficient location may be in the centermost area of the building for even distribution of ducting.

Split systems were commonly “ducted” until the invention of the mini-split, which are mainly ductless (the exception being special-order ducted mini-split systems). 

How Does a Split System Work?

A split system uses two or more components to control the temperature of a building. It is usually composed of one or more indoor evaporator units that contain an evaporator coil and an outdoor condensing unit that contains a condenser coil. The two components are connected via refrigerant pipes to circulate refrigerant. 

As the refrigerant circulates, flowing through the air handler coil – the fan pushes the inside air through the coil, allowing the heat to be collected by the cold refrigerant. The refrigerant circulates to the outside through copper lines to the condenser coil, where a fan removes the heat from the refrigerant.

The outdoor condenser unit cools the refrigerant and pumps compressed hot liquid refrigerant into the indoor unit. The outdoor condensing unit is usually located in an area where noise is less of a concern; it has been known that putting the condenser unit in a shaded area helps with efficiency – in fact, some installers have added sections of privacy fence to keep the cabinet of the condenser out of the direct sun, as its main function is to dissipate heat, not to collect heat from the sun. The outdoor unit is where the heat from inside your home is dispersed. It contains the compressor, condenser coil, and fan.

A wall-hung mini-split system head differs from ducted air conditioning by having a separate compressor and indoor unit for each area that is being cooled (apart from multi-head split systems, which have multiple indoor units attached to the single outdoor unit).

Split System Types

The two most common types of air conditioning split systems are ductless mini-split systems and central air ducted systems. Mini-split systems consist of one or more small, wall-mounted indoor air handlers and an outdoor compressor. These systems are ideal for efficient heating in smaller spaces, as they do not require ductwork. Central air conditioning systems include both an indoor and an outdoor component, with the compressor and fan being contained outdoors and the evaporator coil and blower being contained indoors. 

What Are the Pros and Cons of a Split System?


  • Split system central air is the best option for space-saving. 
  • Versatile and efficient. Split systems are highly versatile since they are available in both ducted and ductless varieties, both of which can provide efficient heating and air conditioning.
  • Space-saving. Ductless split systems are a great option for those with limited space since they don’t require the use of bulky ducts.
  • Lower energy costs compared to multiple window units being used in a house. 


  • Expensive. Split systems can be quite expensive, with costs ranging from a few thousand to several thousand dollars.
  • Installation. Installing a split system can be a complex and lengthy process due to the required refrigeration lines and wiring.
  • Maintenance. Split systems require regular maintenance in order to keep operating efficiently and effectively.

What Is a Ductless Split System?

A ductless split system is an HVAC installation that does not require ducting, making it an ideal choice for a home, apartment, or other small space. These systems are composed of an outdoor condensing unit and one or more indoor evaporator units connected by refrigerant lines. This type of system will maximize the efficiency of your HVAC system and enable you to independently control the temperature in each room.

What Is a Hybrid Split System?

A hybrid split system is an HVAC installation that combines the indoor and outdoor components of both a ductless mini-split system and a central air conditioner. It uses both refrigerant lines and ducting, as well as an outdoor compressor and an indoor evaporator coil. This type of system is ideal for larger spaces and offers improved efficiencies, as well as enhanced temperature control. Hybrid systems often include extra features such as multiple indoor units and integrated humidity control.

What Is a Mini-Split System?

A mini-split system is a split system composed of one or more small, wall-mounted indoor air handlers and an outdoor compressor unit. Mini-split systems, designed for single spaces, such as an added room, basement, or garage, are wall-hung, individually controlled, and operated systems. Mini-split split systems enabled service in areas never considered, such as hobby sheds, vegetable storage sheds, and cabanas. These systems are ideal for efficient heating in smaller spaces, as they do not require ductwork. The mini-split system circulates cooled or heated air from the two components, depending on the temperature in the building. Mini-splits are mostly ductless; however, there are some manufacturer-engineered ducted mini-split systems. 

What Is an Inverter Split System?

An inverter split system is an HVAC installation that utilizes both a split system and an inverter to regulate the operation of the system. The inverter is used to adjust the fans and motors to ensure they achieve maximum efficiency. Additionally, these systems typically use variable speed technology, which accurately maintains the temperature inside the building. Inverter split systems are capable of operating more quietly than conventional systems and can offer improved energy savings.

What Is the Difference Between a Split System and an Inverted Air Conditioner?

A standard split system functions with an on-and-off command concept. Once the inverter is applied, all moving parts (compressor, fan motors, etc.) become variable speed, increasing the split system air conditioner’s efficiency. Inverter technology can improve the efficiency of split system air conditioners as it can adjust the compressor speed to account for changes in temperature. An inverter split system uses around 30% less energy than a standard fixed-speed split system.

What Is a Split System Air Conditioner?

When selecting a split system, it’s important to realize that some split systems are specified as “straight cool” or cool-only and should be labeled as such. A split system air conditioner is a split system heat pump that is straight cool or cool-only. 

What Is the Difference Between a Split System and an Air Conditioner?

A split system has the condenser and air handler remotely separated and connected with control wiring and refrigerant lines. A standard air conditioner has both components and parts in one cabinet. An air conditioner, essentially, is a core component of a split system. 

What Is a Split System Heat Pump?

A split system consists of two main components (condenser and air handler) remotely separated from each other with the ability to both cool and heat the air. Some split systems may be called heat pumps but are designed for cool-only; this would be called an air conditioner heat pump. Caution must be taken when purchasing a heat pump, depending on whether you require a straight cool or cool-only heat pump (air conditioner heat pump) or a heating and air conditioning split system (HVAC split system).

A split system heat pump is an HVAC system that is designed to both heat and cool a building. It consists of two main components: an outdoor condensing unit, which houses the compressor and fan, and an indoor evaporator unit containing the evaporator coil. The difference between a split system heat pump and a traditional air conditioner is that the heat pump can move heat from one space to another rather than just cooling the air. This process is called “reverse-cycle refrigeration,” and it enables the system to both heat and cool a space more efficiently.

What Is the Difference Between a Split System and a Heat Pump?

A split system is made up of two components remotely separated, the condenser unit and the air handler unit. A heat pump transfers heat from one location to another. A heat pump itself can be considered a split system. 

What Is the Difference Between a Split System and a Package Unit?

Split systems have the condenser unit and the air handler remotely separated from each other and connected with control wiring and copper refrigerant lines. The package unit contains both the air handler and the condenser unit in one cabinet. 

What Is the Difference Between a Split System and a Furnace?

A split system consists of two separate main components (air handler and condenser unit) connected with wiring and refrigerant lines. A furnace is a standalone unit, while split systems require both indoor and outdoor units. A furnace is commonly part of the air handler within a hybrid split system. A furnace is an auxiliary component of a split system that generates heat. 

What Is the Difference Between a Split System and an Evaporative Cooler?

A split system has three main functions: control heat, control cool, and remove humidity. An evaporative cooler uses heavy humidity to cool the air. Evaporative coolers are a very poor choice. A split system air conditioner uses two components to cool a space, a condensing unit and an evaporator coil, to remove humidity. An evaporative cooler applies humidity by using a fan to draw in outdoor air, passing it through an evaporative pad to cool the air. Split systems are generally more efficient than evaporative coolers and offer better temperature control. An evaporative cooler is not part of a split system. 

How Much Does a Split System Cost?

The price of the split system can vary from $600 for a single-zone system to over $20,000 for a multi-zone set-up for an entire house. The amount of money that needs to be spent can fluctuate depending on various conditions such as the kind of system, the magnitude of the project, and the intricacy of the setup.

Are Split Systems Efficient?

Split systems are among the most cost-effective air conditioning systems for the home. With SEER2 engineering, we are seeing the most efficient systems ever manufactured appearing on the market. There are numerous factors implemented to cause this efficiency: the use of a thermostatic expansion valve for refrigerant flow control and the variable speed compressor and fan motors which eliminate the constant hard-start on energy consumption spikes. 

Do Split Systems Cost More to Heat or Cool?

New SEER2 systems are extremely efficient at both heating and air conditioning; however, the upfront costs are high. Once up and running, fantastic savings on energy (electric bill) will be around for a long time. The difference in energy consumption should only take a short few years to recap the cost difference.

How to Size a Split System?

In order to determine which type and size of a split system is best for your needs, you will need to take into account the size of your space, the climate in your region, and other factors such as the number of occupants and the orientation of the building. It is important to have a qualified HVAC technician assess your space, as they can provide you with guidance on the most suitable system for your specific needs.

Can a Split System Cool a Whole House?

With a correctly designed system in place, a split system is capable of cooling an entire house. Ductless mini-split systems offer a convenient way to heat and cool one room or area of your home. There are also multi-zone mini-split systems that can provide heating and air conditioning to multiple areas or potentially your entire home.

How Many Rooms Can a Split System Cool?

A properly sized split system is capable of cooling every room in your home through the central air concept with the use of ducting. Some new concepts on the market are offering electric dampers, which add zoning to the central air system. Many homes today may actually have two, three, or more split systems breaking the house up into different system services areas. Another good benefit to having multiple systems is the potential system breakdown – the entire house will not go unserved. 

How to Install a Split System?

A well-engineered split system and an experienced contractor should have no problem with installation. Below are some split system installation factors: 

  • Most importantly, an energy study must be performed on the building structure. Once the energy study is completed, you will have the size of the unit necessary for the size of the building structure. 
  • The electrical supply has to be considered to energize the chosen system. 
  • The duct sizing and routing must be engineered.
  • The locations for the air handler and condenser units must be selected and installed.
  • The tradesman should be asked to install all ducting, electrical, and drain piping. 

A split system installation will take around 3-6 hours. The exact time can vary based on many factors including system type, size, and complexity of the installation. Installation should be performed by a licensed expert.

How Much Does Split System Installation Cost?

The average cost of installation for a split system is between $2000 to $9000. Split system installation cost can be the material cost and a 100% markup for installation labor. Installation costs will vary widely depending on the split system type, size, ducting, and complexity of installation.