What Is a Mini-Split?

By Anne Fonda

A mini-split, also known as a ductless mini-split or ductless mini-split system, is a ductless heating and cooling (or cooling only) system. Instead of pushing heated or cooled air through ductwork, the system sends heated or cooled air into a space through one or more indoor units.

These systems are ideal for older homes with no existing ductwork, new construction, home additions, enclosed patios/porches, garages, and other areas.

How does a mini-split work?

A ductless system consists of an outdoor ductless mini-split heat pump and one or more indoor mini-splits, depending on the type of system. The outdoor and indoor units are connected by refrigerant lines.

The ductless heat pump works using the same technology as a split-system ducted heat pump. Using heat energy and through heat exchange, it transfers heat to a cooler or warmer environment. 

In cooling mode, the refrigerant absorbs heat inside the home and transfers the heated refrigerant to the outdoor unit where the heat is released. In heating mode, the process is reversed.

Our ductless systems use advanced technology to cool your home on the hottest days and heat your home even in frigid weather. You control the temperature with a remote control. Simply aim it at the unit and adjust it to your comfort level.

What are the types of ductless mini-split systems?

The two types of systems are single-zone and multi-zone.

Single-zone ductless mini-split systems

Single-zone mini-split systems have one outdoor unit and one indoor unit. They provide heating and cooling for an individual room or zone. Work with an HVAC professional to choose the right unit for your needs.

Cooling only

While most ductless HVAC offer both heating and cooling, we do offer a ductless mini-split air conditioner option that offers cooling only. A mini-split AC unit might be a good option for a garage in a moderate climate or to cool an upstairs room that needs a boost, such as an exercise room.

Multi-zone ductless mini-split systems

Multi-zone systems consist of one outdoor ductless heat pump and up to 8 indoor units (with our systems). These multi-zone ductless heating and cooling systems are suitable for:

  • New construction for optimal zoned heating and cooling efficiency
  • Adding energy-efficient heating and cooling to an older home or cabin without ductwork
  •  Adding heating and cooling to a home addition without the cost of adding ductwork
  • Heating and cooling an insulated attic or basement without ductwork

There are many mini-split heating and AC configurations. Some of the most popular include:

  • Dual-zone mini-split/2-zone mini-split
  • 3-zone mini-split
  • 4-zone mini-split
  • 5-zone mini-split

The layout of your home will help determine how many zones you need. Work with an HVAC professional with specialized training in designing and installing ductless systems for the best results.

What are the types of indoor units?

There are three types of styles and mounting locations when it comes to indoor ductless units. Which type(s) you choose will be based on your space and your aesthetic. Work with an HVAC professional to understand the benefits of each mounting location.

Your choices include:

  • Ceiling mount mini-split (aka mini-split ceiling cassette)
  • Wall mount mini-split
  • Floor-mounted mini-split

All three types are available with both single-zone ductless systems and multi-zone ductless systems.

What size mini-split do I need?

Accurate sizing is essential to get the optimal heating and cooling efficiency from a ductless system. Again, work with an experienced HVAC professional for optimal results.

Factors to consider in the proper sizing of a system include:

  • Square footage
  • Ceiling height
  • Climate
  • Sun exposure
  • Insulation

What does mini-split installation cost?

Your ductless system cost will vary depending on several factors, including:

  • Single-zone or multi-zone
  • Type of indoor unit(s)
  • System efficiency and capacity
  • Complexity of the installation
  • Brand
  • And more

The best way to calculate your estimated cost is to work with HVAC professionals experienced with ductless systems.

Why Mitsubishi mini-split systems?

American Standard has partnered with Mitsubishi Electric to offer Mitsubishi mini-splits to homeowners like you. Mitsubishi systems are routinely ranked as one of the best mini-split brands worldwide.

In 1959, Mitsubishi introduced ductless heating and cooling in Japan, and ductless systems are now the norm in the Asia-Pacific region. Ductless systems are also gaining popularity in Europe.

We have partnered with Mitsubishi to bring superior technology to the residential mainstream in the United States. With these highly energy-efficient systems, you may be able to save energy and reduce your energy consumption by up to 40% over conventional systems.

Schedule a consultation

If you’re considering heating and cooling (or just cooling) your home with a ductless system, make sure you work with HVAC professionals who have designed and installed ductless mini-split systems before. Contact your local American Standard dealer today for a consultation.


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 Ryan Goodwin, Senior Product Manager, Ductless

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