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What is AC Ductless System, and How Does it Work?

Summers can be brutal, and a reliable air conditioning system is crucial for staying comfortable and healthy. While central air conditioning systems are a popular choice, they are not always practical for every home. Enter ductless AC systems, also known as mini-splits, which are highly efficient and flexible options for cooling your home. In this article, we will explore what a ductless AC system is and how it works.

What is a Ductless AC System?

A ductless AC system is a type of air conditioning system that operates without ducts. It consists of an outdoor compressor unit and one or more indoor air-handling units, which are connected by a conduit that contains the power cable, refrigerant tubing, and condensate drain. The indoor units are mounted on the wall or ceiling and blow cool air into the room, while the outdoor unit dissipates heat.

How Does a Ductless AC System Work?

A ductless AC system works by using the same principles of refrigeration as a central air conditioning system. The outdoor compressor unit circulates refrigerant through the indoor air-handling units via the conduit. The refrigerant absorbs heat from the indoor air and carries it to the outdoor unit, where it is released into the outside air.

Here’s a step-by-step breakdown of how a ductless AC system works:

  1. The indoor unit blows warm air from the room over the evaporator coil.
  2. The evaporator coil contains refrigerant that absorbs heat from the warm indoor air, cooling it down.
  3. The refrigerant, now in a gaseous state, is pumped to the outdoor unit.
  4. The outdoor unit compresses the refrigerant, which causes it to release the absorbed heat into the outside air.
  5. The refrigerant, now in a liquid state, is sent back to the indoor unit to repeat the process.

Advantages of a Ductless AC System

  1. Easy Installation: Unlike central air conditioning systems that require extensive ductwork, a ductless AC system is much easier and quicker to install.
  2. Energy Efficiency: Ductless AC systems are highly efficient because they don’t have the energy losses associated with ductwork.
  3. Zoning: Ductless AC systems allow for individual temperature control in each room or zone, which can lead to significant energy savings.
  4. Flexibility: Ductless AC systems can be used in a variety of applications, from small apartments to large homes and commercial buildings.
  5. Quiet Operation: Ductless AC systems are known for their quiet operation, making them a great option for bedrooms, living rooms, and other spaces where noise can be disruptive.
  6. Improved Indoor Air Quality: Ductwork in central air conditioning systems can accumulate dirt, dust, and other pollutants, which can negatively impact indoor air quality. Since ductless AC systems do not require ductwork, they can improve indoor air quality by reducing the amount of pollutants in the air.
  7. Cost Savings: While the initial cost of a ductless AC system may be higher than a window unit or portable AC, the energy savings and efficiency of a ductless AC system can lead to long-term cost savings.
  8. Increased Home Value: Installing a ductless AC system can increase the value of your home, as it is considered a desirable feature by many homebuyers.

Disadvantages of a Ductless AC System

While ductless AC systems offer many advantages, there are also some potential disadvantages to consider:

  1. Higher Initial Cost: As mentioned earlier, the initial cost of a ductless AC system can be higher than other types of AC systems, such as window units or portable ACs.
  2. Installation Process: Although the installation process is relatively simple compared to traditional central air conditioning systems, it still requires professional installation, which can be more costly.
  3. Aesthetics: Some homeowners may not like the look of the indoor units mounted on the walls or ceilings, as they can be more noticeable than traditional ducted systems.
  4. Limited Cooling Capacity: While multi-zone systems can cool multiple rooms, they may not be as effective at cooling large open spaces, such as a living room or kitchen.
  5. Maintenance: While ductless AC systems require less maintenance than traditional central air conditioning systems, they still require regular cleaning and maintenance to ensure optimal performance.
  6. Limited Heating Capability: While ductless AC systems can provide both heating and cooling, they may not be as effective at providing heat in extremely cold temperatures, and may require supplemental heating sources.

Overall, while ductless AC systems may not be the best fit for every situation, their many advantages, including energy efficiency, improved indoor air quality, and cost savings, make them a compelling option for many homeowners and commercial spaces.

Types of Ductless AC Systems:

There are two main types of ductless AC systems: single-zone and multi-zone.

  1. Single-zone systems consist of one outdoor unit and one indoor unit, and are typically used to cool a single room or small space.
  2. Multi-zone systems consist of one outdoor unit and multiple indoor units, and are designed to cool multiple rooms or zones. Multi-zone systems are a great option for larger homes or commercial spaces.

Installation of a Ductless AC System:

The installation of a ductless AC system is a relatively simple process that can be completed in a few hours. A licensed HVAC technician will first determine the best location for the outdoor unit, then drill a small hole in the wall to connect the conduit. The indoor units are then mounted on the wall or ceiling, and the technician will connect the refrigerant lines and power cables to the outdoor unit. Once the installation is complete, the system will be tested to ensure it is functioning properly.

Maintenance of a Ductless AC System:

Proper maintenance is important to ensure the longevity and optimal performance of a ductless AC system. Some maintenance tasks that should be performed regularly include:

  1. Cleaning the air filters in the indoor units once a month.
  2. Clearing any debris from the outdoor unit.
  3. Checking the refrigerant levels and adding more if necessary.
  4. Professional cleaning and maintenance at least once a year.

Frequently Asked Questions

Q: How many indoor units can be connected to one outdoor unit?

A: The number of indoor units that can be connected to one outdoor unit depends on the model and capacity of the system. Typically, a single outdoor unit can handle up to four indoor units.

Q: How often should I clean my ductless AC system?

A: It is recommended to clean the air filters in the indoor units once a month to maintain optimal performance. Professional cleaning and maintenance should be done at least once a year.

Q: How long do ductless AC systems last?

A: With proper maintenance, a ductless AC system can last up to 20 years.


A Ductless AC system is an efficient and flexible option for cooling your home or commercial space. With easy installation, energy efficiency, zoning capabilities, improved indoor air quality, and cost savings, it is no wonder that ductless AC systems are becoming more popular. Whether you choose a single-zone or multi-zone system, proper maintenance is key to ensuring optimal performance and longevity of your system. If you are considering a new air conditioning system, a ductless AC system may be the right choice for you.

Learn More About Ductless Systems

Do you still have questions about channel less systems? Carrano Air HVAC Contractor Inc. experts can help! We work with homeowners every day to find the best and most affordable ductless mini split system for their needs. Call us today to speak to one of our experts. Also, ask about our other heating and air conditioning services including installation, repairs and maintenance, as well as upgrades that help you save money like programmable thermostats. We offer a 24×7 emergency repair service so we’re there when you need us!


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