How to Install Ductless Split Air Conditioning

Written by leah newman
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How to Install Ductless Split Air Conditioning
Mini-split unit are a ductless alternative to window units. (Jupiterimages/ Images)

Mini-split air-conditioning units are an economical, energy-efficient alternative to traditional central air-conditioning systems. Mini-splits can be used to provide ductless cooling to your entire home or can be installed to cool just a few areas. A mini-split unit is also perfect if you need to keep some areas of your home cooler than others, since each room unit has its own thermostat. A mini-split system consists of an outdoor condenser and indoor, wall-mounted units that supply the area with cool air.

Skill level:

Things you need

  • Mini-split air-conditioning system
  • Drill
  • Refrigeration line set with couplings
  • Pipe insulation

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  1. 1

    Determine where you will place the exterior condenser. The condenser unit can be installed on the ground or on the roof, but it should be placed on a concrete slab, pavers or patio stones to ensure proper air circulation around it. Some manufacturers also offer wall-mounting hardware to secure the condenser to an exterior wall.

  2. 2

    Attach the mounting hardware for the indoor unit using screws and a drill.

  3. 3

    Drill a 3-inch hole through the wall behind where the indoor unit will be installed. The hole should reach through to the exterior wall of the house.

  4. 4

    Connect the defrost wire to the wire with matching black couplings. Attach the drain pipe tube to the drain port on the unit. Run copper pipe to form the feed and return lines, connecting them to the indoor unit with couplings. Wrap the copper pipe in insulation made for this purpose and secure with tape.

  5. 5

    Run all wires and pipes, including the electrical connection going to the compressor, through the hole in the wall and to the outdoor unit.

  6. 6

    Contact a certified HVAC technician. The final connection and pressurisation of your mini-split system requires expert knowledge and specialised tools. A professional will wire the electrical connection to the compressor, connect the copper piping, flush and pressurise your system, and charge it with R-410a "Puron" refrigerant. Attempting to do any of this without certification may damage your system and will void your system warranty.

Tips and warnings

  • Install the room units over 6 feet from the floor, with a minimum of 4 inches from the ceiling. This will provide the greatest efficiency from your system.

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