What is a Ductless HVAC System?

• Posted in Air Conditioners, General Articles
• on August 18, 2012
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Ductless HVAC systems do not use ductwork to distribute air. These mini-split HVAC systems send treated air directly into a room or zone using an air handler to distribute the air.

How Ductless HVAC Systems Work

Ductless systems can be AC-only or heat pumps that supply both heating and air conditioning.

These systems are called mini-split systems since they work similarly to a full-scale split HVAC system but are not connected to the ductwork, and they typically serve a smaller area.

The condensing unit is located outside the building, usually directly adjacent to the area it will be treating. An air handler is installed inside, often high on a wall or sometimes in the ceiling. The air handler contains a fan to facilitate air flow and may also have directional louvers. The louvers can sometimes be controlled with a remote since the air handler installation location makes them difficult to reach.

A power line and refrigerant lines connect the air handler to the condensing unit, and a drain line carries condensate out of the building.

When cooling, the refrigerant picks up heat in a coil inside the air handler and carries it outside where it radiates into the environment through a second coil. A fan helps to disperse it. This effectively cools the inside of the home. When heating space, the flow of refrigerant is reversed. It collects heat outside and carries it to the air handle to be dispersed. Valves within the system change the direction and operation of the refrigerant.

Single-Split ductless HVAC systems use a single air handler. Multi-split ductless HVAC systems use 2-4 separate air handlers which serve different rooms or zones.

Advantages of a Ductless HVAC System

These systems are ideal for use in existing homes and buildings that do not have ductwork, making a central HVAC system impossible. They are also excellent for home/building additions when it is impractical to extend the current HVAC system.

Secondly, mini-split ductless systems are less complicated to install. The condensing unit can sit on a pad, be attached to an exterior wall or can be placed on a roof. A single small hole is made in the wall to run the lines. Air handler installation is also fairly easy compared with installed ductwork and grates.

Finally, ductless HVAC systems are quite efficient. The most efficient offer SEER ratings in the mid-20s, a few points higher than the most efficient central AC splits systems can deliver.

If you are planning a new building or home addition, of if you want to boost the heating and/or cooling of existing space, take a close look at ductless split HVAC systems. Consult a qualified contractor about your choices and the suitability of a ductless system for your home or building. A mini-spit system is an attractive alternative to traditional systems for the right type of installation.