A zone is any room or area served by its own indoor unit, with its own independent temperature control. In a multi-zone ductless mini split system, one outdoor unit connects to several indoor units, so you can heat or cool a bedroom, living room, and office to different temperatures at the same time. Pioneer multi-zone outdoor units support 2 to 6 zones. To figure out how many zones you need, count the rooms or open areas you want to control separately. An open-concept living and dining area can often be one zone, while bedrooms usually work best as their own zones. Hallways and closets are typically ignored.

As a general rule, a room needs about 20 BTU per square foot of living space for cooling only purposes, and increased to 25 BTU per square foot for heating and cooling. If the system will be used as a primary heating source in a cold-climate, 30 BTU per square foot is recommended. Adjust upward for high ceilings, poor insulation, large windows, strong sun exposure, kitchens, or extreme climates, and downward for shaded, well-insulated rooms. Size each zone separately based on that room’s square footage. For a more precise number, use our free mini split BTU calculator to estimate the load for each room. Then enter those results in the configuration wizard.

Measure the actual path the refrigerant lines will travel from each indoor unit to the outdoor unit, including every vertical rise, turn, and drop, not the straight-line distance. Add a few feet of slack for connections, then choose the next available length up. Each zone needs its own line set, so measure every zone separately. Keep in mind that every outdoor unit has a maximum line length per zone and in total, and longer runs may need extra refrigerant. The configuration wizard calculates your total pipe length and any refrigerant adjustment automatically.

A standard copper installation kit includes insulated, pre-flared copper refrigerant pipes with brass flare nuts, plus signal cable, a condensate drain hose, a wall sleeve, filler putty, and wrapping tape. It’s the traditional choice for most installations. EZFlex™ uses stainless steel instead of soft copper, which is prone to kinking or hardening with tight or repeated bends, so EZFlex handles tighter bend radiuses and more complicated routing. It’s a good fit for DIY installs or runs with several turns. One thing to know before ordering: EZFlex can’t be shortened, patched, or repaired, so measure carefully and pick a length that covers your full run. 

Yes, and it’s common. The number of circuits (or zones) on an outdoor unit is the maximum number of indoor units it can connect to, not a requirement. You can leave one or two connections unused. Because the outdoor unit’s total capacity is shared across every indoor unit connected to it, connecting fewer units means each one gets more of that capacity. For example, a 4-zone, 36,000 BTU outdoor unit connected to just two 18,000 BTU indoor units works as a more powerful dual-zone system. Before you buy, check the compatibility chart to confirm your combination is supported, or let the configuration wizard match it for you.