Relatively new to North America, mini-splits originated in eastern Asia during the mid-20th century. Due to the clustered layout of their neighborhoods, the Japanese needed to find a quiet way to heat and cool buildings without bulky equipment. Mini-Split technology continues to improve, but its principles have remained unchanged: indoor units connected to outdoor units with line-sets.
The configuration of ductless mini-split systems offers several advantages. All the noise-generating functions of the system take place at the outdoor condensing unit – out of sight, out of mind, and out of hearing range. Insulated line-sets run refrigerant between the indoor unit(s) and outdoor unit. Most mini-splits use R-410A refrigerant. Line-sets have a liquid line and a suction line, which must be sized based on the specifications of each indoor unit. They range in length depending on the application, and may be ordered with pre-flared ends for easy connections. An electrical line must also run between the units. Indoor units receive their power from outdoor units. This set-up does not clutter the living space with extra wires. Outdoor units generally require a dedicated electrical circuit.
Depending on the units involved, multiple indoor units can operate with a single outdoor unit. In multi-zone applications like these, each indoor unit needs to be fed by a separate line-set. The indoor units must be controlled by a remote control, but wall-mounted thermostats can usually be purchased separately.
Mini-Split systems offer optimal zoning efficiency. Each indoor unit operates independently of the others. During the day, units in bedrooms can remain off or operate on lower settings, while kitchen or living room units can do the same at night.
Most modern mini-splits operate with Inverter technology, perhaps their biggest energy-saving feature. This technology allows the compressor, part of the outdoor unit, to adjust its revolutions to the needs of the system. It accomplishes this by converting input power from AC to DC. Inverter-controlled compressors reduce the amount of incoming power required and are much more cost effective than standard air conditioners, whose compressors can only turn on and off. As an added bonus, the outdoor unit will make less noise.
In addition to saving space and operating efficiently, mini-splits do not require ductwork. Central air conditioning ducts allow air to leak and, ultimately, waste energy. Window air conditioning units do not operate with Inverter technology. Their compressors run at the same level whenever they are on. They block access to windows and bring compressor noise into the home.
As with all air conditioners, mini-split systems must be sized based on BTUs (British Thermal Units). Each indoor unit must be large enough to remove enough heat (measured in BTUs) to keep the space it controls cool. SupplyHouse.com offers a convenient sizing calculator to help estimate requirements for specific jobs. Click here to go there now. Outdoor units will also have a BTU rating. In order to operate at full capacity, the combined BTU rating of all indoor units must not exceed the outdoor unit’s rating. Certain units can also function as heat pumps. They have a separate BTU capacity for heating.
Installers can anchor outdoor units to the ground or use an optional mounting bracket. It makes the most sense to position indoor units on the upper part of the wall. Cool air will drop to the living space, as warmer, more humid air vents out of the room. Placement on exterior walls simplifies condensate drainage and installation. Ceiling cassette systems may be used when space is an issue, but may require limited ductwork.
Has this piqued your interest in mini-splits? Check out SupplyHouse.com for our selection of Mini-Splits (click here) from top brands like LG and MR Cool. Ever use mini-splits yourself? Let us know about your experience in the comments section below.