Mini Split Components: Air Handlers & Outdoor Condenser Units

A ductless mini split has two main units: an indoor air handler that contains the evaporator coil, blower, and air filter, and an outdoor condenser unit that houses the compressor, condenser coil, and fan. They are connected by an insulated refrigerant line set, a condensate drain that carries away moisture, and electrical and communication wiring that coordinates compressor speed, fan output, and temperature control. Most failures in ductless systems are component-level issues, such as a control board, fan motor, sensor, or a blocked drain, rather than a failed system. Knowing which unit a part belongs to makes it much easier to shop for the right replacement.

Yes, indoor and outdoor units are sold separately, which is useful for replacing a failed unit or adding a zone to an existing system. The catch is compatibility: an indoor unit only works with the outdoor units its manufacturer approves, and the listing will usually name the matching series or model. For example, the Daikin FTXR12TVJUS indoor unit lists the RX12RMVJU9 as its required outdoor unit. Browse the mini split outdoor units collection and confirm the pairing against your existing model numbers before ordering.

Start with the model numbers on the nameplates of the units you already have, since manufacturers publish which indoor units pair with each outdoor unit. Then confirm four things: the brand and series, the capacity in BTU, whether the outdoor unit is single-zone or multi-zone, and the refrigerant type. Voltage and line connection sizes matter too, and many indoor units use a 1/4 inch liquid line and a larger suction line. If the product page does not state the pairing clearly, send us the model numbers and a specialist will confirm the match before you buy.

Indoor units are sized in BTU, and a common rule of thumb is about 20 BTU per square foot of living space. Under average conditions with standard 8 foot ceilings and normal insulation, a 9,000 BTU unit covers roughly 250 to 450 square feet, which suits bedrooms, home offices, and small studios. Higher ceilings, strong sun exposure, poor insulation, and heat-generating equipment all push the number up. An oversized unit short-cycles and leaves humidity behind, while an undersized unit runs constantly, so if you are between sizes, request a quote and we will help you choose.

Wall-mounted units are easy to install and more affordable upfront, and they suit smaller rooms with direct airflow in one or two directions. Ceiling cassettes distribute air in all directions from a flush ceiling mount, which works well in larger open spaces but costs more to install and needs accessible ceiling space. Floor-mounted units sit low along a wall or under a window, and concealed duct units hide above the ceiling and deliver air through short duct runs. You can see every style in the mini split air handling units collection, and different styles can be mixed within a multi-zone system.

Both are in use. Many indoor units on this page, including several Mitsubishi, LG, and Daikin models, are listed with R-410A, while newer outdoor units are increasingly available with R-32, which has roughly one-third the global warming impact of R-410A (R-32 has a GWP of about 675 against about 2,088 for R-410A). The two refrigerants are not interchangeable, so the indoor unit, outdoor unit, and any replacement parts should all be designed for the same one. R-32 is classed as an A2L refrigerant, so it should be installed by a qualified technician who follows the manufacturer's safety requirements.

The most commonly replaced components are control boards, inverter modules, fan motors, thermistors and temperature sensors, and condensate pumps. A blocked condensate drain is also among the most frequent causes of service calls, and it is often a maintenance issue rather than a failed part. When you order a replacement board or sensor, match it by the full model number and the revision number printed on the part, because a similar looking component can be incompatible. If you are not sure which part has failed, a technician can diagnose it before you buy.

Select in-stock items ship the same day when ordered before the cutoff shown on the listing, and larger indoor units ship by freight, typically in 1-3 business days with a lift gate where noted. Inspect the packaging when the delivery arrives. Several of the listings on this page are final sale with no returns, except for items that arrive damaged or defective, so check the return terms on the product page and confirm the model and compatibility before you order.