What Is a Ductless HVAC?

ac unit

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Older homes and apartments often relied on window units to provide cooling during the summer. Although these units are efficient, they can be noisy and unsightly, and they don’t usually have the capacity to cool large areas.

Ducted Heating, Ventilation and Air Conditioning (HVAC) systems are common in new homes that can afford them. However, they are expensive to install in existing homes, require extensive home remodeling, and don’t offer as much flexibility as ductless mini splits.

Ductless mini splits put the indoor air conditioning or heating units as close to the outside walls as possible to reduce the amount of pipe connections required for ventilation. Their technology has improved significantly to allow even greater customization with remote controls, timers, Wi-Fi compatibility, and other features.

What Is a Ductless HVAC?: Basic Mechanics

Central air conditioning and other ducted systems require installing ducts to move air from an indoor unit throughout the house. These ducts are usually in the floor, wall, or ceiling and dispense cooled or heated air into a room through a vent with grates.

Ductless systems place a single indoor unit in each area that you want heated or cooled, connecting them with some simple tubing to an outdoor unit. The indoor unit of a mini split system pulls the air from inside your home over heated or cooled coils. The outdoor unit absorbs all the unwanted heat using a special refrigerant and serves to drain condensation from inside the indoor unit.

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Usually, one outdoor unit connects to multiple individual indoor units, but each installed indoor zone can still be controlled separately. You can control the temperature, fan speed, fan direction, and other variables more precisely than you can with traditional central air. Many homes will have at least two separate zones so all members of the family can stay comfortable.

man installing an AC

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Installation Process

Ductless heating and air conditioning units require small holes to be cut in an outside wall. Typically, the indoor unit is installed on the inside of this wall, but it can also be installed on an interior wall if necessary.


You can choose from ceiling-mounted or wall-mounted units. Although ceiling-mounted units usually require more work to install, they are less noticeable and won’t interfere with your wall decor.

Most manufacturer warranties, including those for Mitsubishi ductless HVAC systems, require the system to be installed by a licensed HVAC professional in order for the warranty to be valid. However, the installation costs and time are still much lower than with ducted systems. In most cases, the installation can be completed in a single day with minimal interruption to your life around the house.

Overall Capacity

Despite their ease of installation, ductless HVAC units can heat or cool your entire home. Unit capacity varies, but they can commonly cool 1,300 ft² or more. If you have a small home with an open floor plan, you could heat or cool the entire first floor with one indoor unit in the living room and one in the master bedroom.

However, it’s important to understand the pros and cons of ductless HVAC systems overall since they have capacity limits. It’s best to look at the total number of BTUs associated with a given indoor unit before making your purchase. BTUs measure temperature output and provide a more precise method of measuring capacity than square footage estimates.

This is because your installation needs partly depend on how old your home is and how extreme the outside climate is. Homes with poor insulation and very hot or cold weather may need an extra indoor unit to keep up with demand. 

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woman relaxing under mini-split

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Energy Efficiency

One of the major benefits of ductless systems is they greatly reduce wasted energy and heat loss. Ducts in traditional ducted systems can end up absorbing up to 30% of the heat going through them, which requires your system to work harder to make up for the loss.

Having a separate unit in each room or zone also improves your ability to manage the temperature in rooms where you need it. If you don’t use your bedroom during the day, you can reduce the AC or heat output to save on energy costs. This is especially important in the hottest parts of summer and coldest days of winter but can save you money year-round.

Understanding Your Options

There are dozens of possible ductless HVAC units to choose from and even more possible configurations for your home. ComfortUp can help you sort through your options with our easy-to-understand online ordering system. You can count on our selection of single and multi-zone units to improve your quality of life year-round. 

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