All About Ductless Mini Split Systems: FAQs

A ductless mini split system is a type of HVAC system that provides heating and cooling without the need for air ducts. Instead, ductless mini splits use refrigerant lines to transfer heat between an indoor and outdoor unit.

The outdoor unit contains the condenser or compressor, while the indoor unit contains the air handler that disperses air. You must have both indoor and outdoor units, as they operate in tandem with each other to produce heating and/or cooling.

Ductless mini splits have many advantages over traditional HVAC systems. They are cost-effective alternatives to central air systems, as they are much less expensive to install.

Because they don’t require ductwork, they accrue more energy savings as well. Duct losses are a major contributor to excessive energy expenses. According to the Department of Energy, duct losses can account for more than 30% of energy consumption for space conditioning.

Mini split systems also require less space and are not as obstructive. The dimensions of a condenser, or the outdoor unit, usually measure smaller than a central air condenser. The indoor unit can also mount on a wall or ceiling where a vent would normally go.

With a multi-zone mini split system, you can have multiple indoor units with individual temperature controls. This gives the user unmatched space control that ducted central systems do not offer.

A ductless mini split system consists of three components: the indoor air handler, the outdoor unit, and the conduit.

The air handler, or indoor unit, facilitates movement of the air within the room. It works in conjunction with the outdoor unit to transfer warm air from one place to another.

Depending on the type of mini split system, an outdoor unit can be one of two things: a condenser or a heat pump. A condenser provides cooling for a mini split air conditioner. It contains condenser coils, refrigerant, an expansion valve, and an air filter. A heat pump, which combines a condenser and an evaporator, provides heat for a mini split heater.

Some mini splits have both a heat pump and a condenser, giving them dual heating and A/C capabilities.

The conduit is the final part of a mini split system that connects the indoor unit to the outdoor unit. It houses the necessary wiring connecting the air handler and the condenser or heat pump. The conduit is also where the condensate drain and refrigerant line sets are.

No, you do not need a condenser for every air handler in your mini split system.

Single-zone mini split systems include one air handler and one condenser. One air handler can regulate the temperature in one room or space.

Multi-zone split systems include two to four air handlers and one condenser. Each air handler goes in a different room, and they all connect to one outdoor condenser. Some condensers can manage up to eight air handlers.

The air handler is a part of the indoor unit, and you can place it in any space that requires heating or cooling. Typically, indoor mini split units mount on the wall or ceiling to disperse air evenly throughout a room. This also prevents air flow blockages and obstruction of space.

Some types of spaces you might install an air handler are garages, basements, small apartments, and room additions.

You typically install condensers and heat pumps on the exterior of your home or building. The best position is close to where your air handlers are on the inside. The length of the refrigerant lines and wires set the limit of distance between the two units. The shorter it is, the less your system's installation costs will be.

For the best results, install your condensers or heat pump on the ground atop a cement pad or wall mounted bracket. This protects the unit from harmful environmental effects that could damage or corrode it.

Different manufacturers have different methods of control for their mini split heating and cooling systems. Some mini split systems have a thermostat on the unit, while others can be compatible with a wall thermostat. In some cases, mini splits even have remote or smart control capabilities.

MRCOOL offers an IR WiFi Thermostat for their ductless mini splits. They also offer a mobile application, which allows you to use a phone or mobile device as a remote control.

Mini split systems typically last an average of 20 years. However, you can shorten or extend this lifespan by how well you maintain your system. Cleaning your units and air filters monthly will keep your system in top condition. We also advise hiring an HVAC professional for bi-annual tune-ups to stay on top of maintenance.

Technically yes, but HVAC professionals do not recommend replacing only the air handler or condenser/heat pump. To ensure that the units are compatible, the best practice is to replace both simultaneously. Replacing one and not the other may compromise the integrity of the units and incur more costs in the long term.

Unless you have previous HVAC installation experience, we always recommend consulting a professional. Oftentimes, they have the necessary skills and certifications to handle things like refrigerant and electrical wiring.

However, some manufacturers design their units with DIY capabilities. MR COOL's DIY mini split series are ideal systems for the at-home handyman. The series includes pre-charged lines and installation guides that do not require special tools or training. Though, to wire the system to the house, you will likely still need the assistance of an electrician.

Browse HomElectrical’s selection to find the best mini split system for your heating and cooling needs!