A ductless HVAC system (also called a ductless mini-split or ductless multi-split) is a heating and cooling system that operates without the use of ductwork. These systems offer precise home comfort and temperature control for one or more spaces, depending on the mini-split system you choose.
By Anne Fonda
A mini-split system uses individual wall or ceiling-mounted blowers to provide temperature control to one or more rooms. Instead of using ductwork and a series of registers and return air vents, the individual indoor units are connected by a refrigerant line set through a small hole in an exterior wall to a single outdoor condensing unit. The outdoor unit is called a mini-split heat pump or ductless heat pump.
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A ductless HVAC system works by circulating refrigerant through a line set connected to one or more indoor air handlers. The ductless HVAC units are typically mounted on an interior wall, either high on the wall or at the floor level.
The indoor mini-splits circulate the cooled or heated air throughout the room. Heat is transferred between the air inside the room and the refrigerant in the indoor unit and is then returned to the outdoor condensing unit, where the refrigerant is compressed and circulated back to the indoor units in a continuous cycle. This process of transferring heat from indoors to outdoors helps keep your home’s temperature at ideal levels.
There are several types of mini-split systems, including:
You control each mini-split with a remote control or through the kumo cloud® app on your phone. You can keep one room warmer and another room cooler, based on your preferences. All mini-split units must be in the same mode at any given time – either heating or cooling.
A ductless system can be a great option for heating and cooling (or just cooling) one room or an entire home that doesn’t have ductwork. For cooling only, you would want a mini-split air conditioning system. A mini-split system might be your best choice for:
If you choose to install a ductless system, just be sure to work with an HVAC professional with extensive experience with these systems.
It depends. If you have a multi-zone ductless system to provide cooling only or heating and cooling for your entire home, you will want to work with an HVAC contractor with extensive experience in designing and installing multi-zone mini-split systems. Some units can serve larger areas. For example, an open-concept home and a home with lots of smaller rooms would need a different system design.
If you are building a new home or renovating an older home, you may be exploring both options. Here are some common questions about mini-split systems that can help you decide whether a ducted or ductless system is a better option.
Not necessarily. It depends on the structure of your existing home, how many mini-splits you need to heat and cool your home, and more. If you don’t have existing ductwork, installing a multi-zone mini-split system may cost less than installing a ducted system where contractors would have to perform major renovations to install a ductwork system.
In general, yes, ductless systems are quieter than ducted systems. The indoor units are whisper-quiet and you won’t hear any “pinging” sounds from expanding and contracting ductwork. Trane/Mitsubishi outdoor units operate as quietly as 46 decibels – the level of a typical conversation.
They can be, especially if you’re talking about installing a ductless HVAC system in new construction. Not needing to install ductwork saves time and money. They are still complicated systems and should only be installed by a trained and licensed HVAC professional.
In general, mini-split systems take up less space than a ducted system. You don’t have a utility room, attic, or crawl space filled with a bulky furnace or air handler. Indoor units are mounted on the wall, at floor level, or in the ceiling. The outdoor condensing units are also smaller than a typical heat pump or central air conditioning unit.
A ductless mini-split system can save you money in the long run because it’s so energy efficient and no conditioned air escapes through leaky ductwork.Trane/Mitsubishi mini-splits use the minimum amount of energy needed to maintain your desired temperature. Depending on the specifics of your home heating and cooling needs, you could reduce energy consumption by up to 40% over a conventional system.
If you’re interested in installing a ductless HVAC system, it’s important to consult with an experienced contractor who can help determine the best units for your needs, as well as make sure that the installation is done correctly and safely. Additionally, proper maintenance is important to ensure that your ductless HVAC system runs efficiently and effectively.
Regular maintenance is essential for keeping your ductless HVAC system running efficiently. This includes cleaning the air filters regularly. Schedule regular ductless mini-split maintenance with an HVAC professional to check and clean the evaporator and condenser coils and check the system’s operation.
Trane and Mitsubishi Electric have a unique partnership when it comes to mini-split and multi-split systems. Each Trane/Mitsubishi mini-split is made by Mitsubishi Electric Trane HVAC US (METUS), based in Suwanee, GA.
Mitsubishi introduced ductless heating and cooling in Japan in 1959, where it has been the norm for decades. The two companies have joined forces to bring superior mini-split technology to the mainstream in the United States.
Trane Ductless Pros (aka Diamond Contractors) have received specialized training in designing and installing ductless systems to ensure you get the unmatched comfort and quality you deserve.
Anne Fonda, Content Writer
A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need.
She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism.
When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.
Expert review by Kimberly Sexton, Senior Systems Engineer
Ductless air conditioning cools just one room or single space where ductwork is not present in your home. Homeowners can install up to five indoor ductless units throughout their home, all connected to just one outdoor unit, in order to cool multiple spaces at once.
Ductless heat pumps work to both heat and cool single spaces or rooms within your home where ductwork is not present. Homeowners can install up to five indoor ductless units throughout their home, all connected to just one outdoor unit, in order to cool multiple spaces at once.
A mini-split HVAC system heats and cools (or just cools) one or more rooms without using a system of ductwork. This is why these systems are also called ductless HVAC systems. A mini-split system is similar to a traditional ducted split system, in that there is an outdoor unit, usually a mini-split heat pump, along with one or more indoor units.
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