Ductless Air Conditioner FAQ

What is a ductless or mini split air conditioner?

splitachouseDuctless air conditioners are a cost-efficient alternative to central air conditioning. They're particularly suited to situations where the complicated ductwork needed for central AC would be costly or impossible to install.

A ductless AC has two main components: an outdoor compressor/condenser unit, and one or more indoor air handling units. The indoor units are wall mounted, and as many as four can be connected to a single system, depending on the cooling needs of your home.

The indoor and outdoor units are connected by a narrow conduit that carries the power cable, refrigerant tubing, suction tubing, and a condensate drain. This conduit runs through small hole drilled in the wall of the building.

Most ductless air conditioners also feature heat pump technology, which allow you to heat your rooms with the same system in the winter.

How does a ductless air conditioner work?


Central air conditioning works by pumping refrigerant from the outdoor condenser unit to a single indoor air handler which cools the air. The cold air is then distributed through the house via a network of ducts.

In contrast, in a mini split air conditioning system, refrigerant is carried from the condenser directly through the conduit to each wall-mounted air handler. A fan draws air across the evaporator coil to cool it, and then distributes it directly into the room.

Why choose a ductless air conditioner?

  • Maintain different temperatures in different parts of the building.
    Each wall-mounted unit has its own thermostat, which means you can control the temperature in each room or "zone" independently from the others. Central AC cannot offer this kind of flexibility - to lower temperature in one room, you must lower the temperature in the whole building.
  • Easier and cheaper to install then central air.
    Even if you have ducts in your building, they will need refitting to accommodate air conditioning. Split AC allows you to avoid ducts all together, and the only necessary construction is a 3-inch hole necessary for the conduit to pass through the wall. However, installation does require an HVAC technician.
  • More energy-efficient then central AC.
    Because the air is cooled and released at the wall-mounted handler, the air does not lose coldness as it travels through the building ducts. Duct losses can account for more than 30% of energy consumption for central air conditioning, especially if the ducts are in an unconditioned space such as an attic. Plus, since you can control the temperature in each zone independently, you don't need to waste money cooling areas that aren't occupied.
  • Quieter to operate than window or portable air conditioners.
    The noisiest parts of any air conditioning system are the compressor fan and condenser motor. With a ductless system, these are isolated outside so the noise won't intrude on your indoor environment.
  • No need to leave windows open.
    When you use a window air conditioner, you must leave the window open, which provides an opportunity to potential intruders. A ductless AC lets you keep windows locked up tight. Plus, you won't have to store it over the winter and reinstall each year when it gets home. Installation is one time only.
Indoor Air Handler Wall UnitOutdoor Compressor-Condenser Unit

How do I choose a ductless AC system?

As with any air conditioner, you need to know the size of the area you wish to cool in order to select the right size unit. Cooling capacity is measured in BTUs, and a good rule of thumb for split ACs is that you will need 12,000 BTUs for every 500 square feet.

Once you have determined the overall square feet, you will need to decide how many zones you want to split the building into. Most mini split systems can accommodate up to four zones, and the total BTU capacity of the system will be divided between the individual capacities of each wall unit. For example, a four-zone 42,000 BTU system might have two 12,000 BTU units and two 9,000 BTU units.

If you need help choosing a ductless air conditioner system for your home, don't hesitate to call and talk to our experts. We're always happy to make sure you get the product that best suits your needs.

Ductless Split Air Conditioners