Ductless Mini-Split Installation Glossary

The indoor air handler is the wall-mounted or ceiling-recessed unit that delivers conditioned air directly into a living space. It contains a coil, fan, and filter that work together to circulate and clean the air. Each air handler operates independently, allowing precise temperature control in different zones of your home.

The outdoor compressor unit houses the compressor, condenser coil, and fan, and is responsible for transferring heat between the refrigerant and the outside air. It connects to the indoor air handler through a conduit containing refrigerant lines, a power cable, and a drain line. Proper placement of the outdoor unit is critical for efficient system performance.

The refrigerant line set consists of two copper pipes that carry refrigerant between the indoor and outdoor units. One line carries cool, low-pressure refrigerant inward, while the other returns warm, high-pressure refrigerant outward. During installation, these lines are routed through a small hole in the wall and must be properly insulated to maintain efficiency.

BTU is the unit of measurement used to describe the heating or cooling capacity of a mini-split system. A higher BTU rating means the system can condition larger spaces more effectively. Selecting the correct BTU capacity for your room size is essential to avoid energy waste and ensure consistent comfort.

SEER, or Seasonal Energy Efficiency Ratio, measures how efficiently a cooling system uses electricity over an entire season. A higher SEER rating indicates greater energy efficiency and lower operating costs over time. Most modern ductless mini-split systems offer high-SEER ratings, making them a cost-effective alternative to traditional HVAC systems.

Zoned cooling and heating refers to the ability to control the temperature in individual rooms or areas independently using separate air handlers connected to one outdoor unit. This setup eliminates the need to condition unoccupied spaces, reducing energy consumption and improving comfort. Zoning is one of the primary advantages of ductless mini-split systems over traditional central HVAC.

A conduit is the protective channel that bundles and routes the refrigerant lines, electrical wiring, and drain hose between the indoor and outdoor units through an exterior wall. Conduits are typically enclosed in a plastic line cover for a clean, finished appearance after installation. Proper conduit installation prevents damage to the lines and maintains system longevity.