How Does Ductless AC Work?

Published on: June 5, 2013

Ductless AC is an HVAC technology that’s innovatively designed to bring greater versatility, increased convenience and improved energy efficiency to the modern home. A ductless system works by connecting an outdoor compressor to one or more compact indoor evaporator units via a narrow conduit that contains a refrigerant line, an electrical power cord, suction tubing and a condensate drain pipe. The outdoor unit delivers cooling — or in some cases heating and cooling — to the home through the indoor air handling units, which can be mounted on the wall or ceiling and each of which contains an evaporator coil to process the air and a fan for distributing the treated air throughout the room or zone in which it is located. Ductless systems make it easy to install an HVAC or AC system in homes that are not designed to accommodate conventional HVAC equipment.

If you have any questions about ductless systems or need help locating an HVAC contractor in the Southeastern U.S. who is qualified to install and service your ductless system, please visit the AC Southeast® Find a Contractor page. This handy resource will help you find a reliable ductless AC distributor-contractor near you.

Who Needs a Ductless System?

Ductless air conditioning is an excellent choice for homes without existing ductwork. These systems are quick and easy to install and won’t require the extensive renovations that a ducted system might. Because a ductless system functions without the need for conventional air ducts, installing a new air duct system will be completely unnecessary when you choose ductless AC.

A ductless HVAC or AC system is also convenient for homes that require supplemental heating or cooling to boost the effectiveness of their central HVAC or air conditioning systems. It also helps to keep room additions and other difficult-to-treat areas of the home consistently comfortable. Adding a ductless system to your existing HVAC or AC system will eliminate the need for extending your home’s ductwork to accommodate the additional room or zone you’ll need to condition.

What Are the Advantages of Ductless Technology?

Ductless HVAC and AC systems offer a variety of advantages that may prove both practical and cost-effective for your home. Some of the main features and benefits that homeowners appreciate about ductless systems follow:

  • With a ductless system, the temperature of each room or zone can be individually controlled.
  • For AC models, the indoor unit for each room or zone can be individually set for cooling, ventilation or dehumidification. Heat pump models also offer a heating option.
  • A conventional HVAC air distribution system, or duct system, is not required for system operation.
  • A ductless HVAC system can be used to cool or heat your entire living space. It can also supplement your existing HVAC system or condition hard-to-reach areas of your home.
  • Ductless systems are fully customizable, allowing you to mix and match indoor and outdoor units to create the system that most closely meets your needs.
  • Ductless systems can be as much as 50 percent more energy efficient than similar-capacity ducted models.
  • A ductless system consists of a single outdoor unit connected to one or more indoor units, which can allow the homeowner to save even more money on utilities by using only those units that condition occupied rooms.
  • A ductless air conditioner can be used in places where portable window air conditioners can’t — such as in a room that doesn’t contain a window.
  • Ductless systems maximize efficiency by eliminating the warm or cool air losses that typically occur with traditional ductwork.
  • Ductless systems eliminate the need for duct cleaning, maintenance and repair.
  • Ductless HVAC systems operate more quietly than their ducted counterparts.

What Types of Ductless Systems Are Available?

Ductless systems come in split system, mini-split system and multi-split system models. Because all ductless heating and cooling systems consist of an outdoor unit and at least one indoor unit, all are considered split systems.

Split Systems

Ductless split system air conditioners, heat pumps and complete HVAC systems are powerful enough to heat and cool a significantly large area. In many milder climates, these systems are sufficient to provide dependable indoor comfort without the need for supplemental heating or cooling. Like all split AC systems, ductless splits consist of an outdoor compressor-condenser unit that powers an indoor evaporator-air handler.

Ductless split systems are available as air conditioners for cooling-only applications or as heat pumps for all-around heating and cooling functions in less-extreme climates. In colder locations, a ductless heat pump can be combined with a ducted furnace to provide “hybrid heat.” This dual heat system can help ensure that even on the coldest nights, you receive sufficient heat and yet still enjoy the energy efficiency of your heat pump as a method for heating your home on milder winter days.

Mini-Split Systems

Mini-split systems, also known as mini splits, are similar to standard split systems, except that they are smaller in size and are designed to target a specific area of the home. This area could be a single room, a workshop, a foyer or another part of the home that is fairly limited in size. These AC systems work well for providing supplemental cooling to those parts of the home that may not be sufficiently cooled by a central air conditioner.

Mini-split ductless heat pumps can also be effective for summer cooling. However, in winter they work just as well for supplementing the heat provided by radiant floor panels, wood stoves, propane or electric space heaters, and other portable heater types, including hydronic heaters, which may prove insufficient for maintaining consistent indoor comfort on very cold days and may not adequately warm outlying rooms or other difficult-to-heat areas without extra help.

Multi-Split Systems

Multi-split systems provide whole-house cooling or whole-house heating and cooling. These systems are designed for connecting several indoor units to a single, more powerful outdoor unit. This space-saving option eliminates the need for more than one outdoor unit, as would be required when installing multiple split or mini-split systems.

Depending on where you live and how you use your system, a multi-split AC or heat pump system can also save you money by potentially allowing you to invest in a smaller-capacity outdoor unit. For example, your usage patterns may not require an outdoor unit that can handle all indoor units simultaneously. If you use only the indoor units in the main living areas of your home during the day and only the units in the bedrooms at night, your cooling and/or heating load requirements won’t be as high. Since ductless systems are fully customizable, your HVAC professional should be able to help you determine the best combination of ductless system components for your needs.

Multi-split ductless systems also provide the option to mix and match the styles of the air handlers you place in each room. For example, if you would prefer a recessed ceiling-mounted unit in your dining room and standard wall-mounted units elsewhere in your home, the system you select should offer that option. Many systems also offer ceiling-suspended and floor-level-installed air handlers, giving you a wide variety of decorative and practical choices for your ductless system.

How Is a Ductless System Controlled?

Most modern ductless air conditioning or HVAC systems feature a remote control unit, though many also offer a wall-mounted control panel. Each indoor unit can be individually controlled, allowing different rooms, or zones, to be treated individually as to temperature setting and whether or not the unit is turned on in the first place. Unlike central heating and cooling solutions, ductless systems are not required to heat or cool every room in your home every time the system is turned on. This is one of their most attractive features.

Multi-split systems often include a master control panel that allows the homeowner to operate each individual unit throughout the home from a single central location, offering even greater convenience. In addition, each air handler can also be operated by remote control, allowing the room’s occupant to adjust the unit’s settings from inside the room or zone.

Look to AC Southeast® for Key HVAC Resources

For more information about ductless air conditioning, visit the AC Southeast® Ductless Air Conditioning Services page. You’ll also find a number of other helpful informational resources by browsing our blog. These ongoing posts will help you better understand ductless systems and many other critical HVAC topics.

If you reside in Alabama, Florida, Georgia, Mississippi, or South Carolina, we can help you find a trustworthy, experienced and credentialed ductless air conditioning specialist who can help you select the right system for your needs. Our contractors are factory-trained and NATE-certified HVAC professionals who are capable of providing a wide variety of services, including installation and ongoing maintenance for your new ductless system. Search our listings today to find the Carrier or Bryant distributor in your area who can help make ductless air conditioning a comforting reality for your home.