How Does a Mini-Split Work?

Ductless air conditioners, otherwise known as ductless mini-split systems, are gaining big popularity in the HVAC world, and for good reason. Offering ultra-efficient, ultra-flexible whole-house cooling and heating, these systems bring impressive temperature control to homes where this would have once been a massive challenge, such as those homes which were not built with the ductwork required in forced-air systems. Since they’re more efficient and offer room-by-room temperature control, many modern homeowners have begun replacing their clunky, inefficient central air with these low-maintenance, adaptable units. If you’re considering making the switch to ductless, it helps if you know a little bit about how they work to see if this is the best option for your home, budget, and needs. ComfortUp is here to help you understand everything there is to know about going ductless.

The Components of a Mini-Split System

The components of a Mini Split system are the indoor unit(s) (called the air handler or evaporator) and the outdoor unit (called the condenser). The indoor unit is generally mounted inside on an exterior wall to make connecting the two components simpler. The indoor and outdoor units are connected by a series of wires and connecting pipes (Linesets), as well as a drain that drains the moisture outside. The evaporator is typically installed on the wall or in the ceiling to allow for easier access to the outdoors. It needs to be placed somewhere where it can effectively distribute air evenly, which is usually closer to the ceiling with a wall-mounted unit. All come with a remote controller, so don’t worry if the unit needs to be installed high up. The outdoor component, the condenser, needs to be installed somewhere with a clear path for venting and somewhere that’s easy for HVAC professionals to access. Because of the appearance of the unit and the pipes that connect the two units, many homeowners prefer to install the condenser on the side or back of the house, so it’s tucked away and doesn’t deter from the aesthetics of your exterior. Your installer should be able to install pipe covers, which can be painted to match your house, for a more attractive look on the exterior.

How Mini-Split Air Conditioning Works

All of the aforementioned components work together to warm or cool your home. When cooling, the system blows warm air from inside your home over a series of cold evaporator coils within the wall-mounted evaporator. When the air runs over the coils, it’s exposed to the refrigerant, which absorbs the heat and sends it through the drain pipe outside. A fan inside the coils helps to dissipate this energy to the outdoor unit. This helps to dehumidify the air and creates a more comfortable environment because lower temperatures can’t hold as much moisture.

How Mini-Split Heating Works

CLICK HERE for a short video to explain but in short, many mini split systems are equipped with heat pumps, so they provide heating in rooms or zones where there is an evaporator unit. Typically, there is a reversing valve in the unit that lets the refrigerant flow in either direction (bringing heat into your home rather than pumping it out), which allows for both heating and cooling within a single unit. When it’s in heating mode, the unit effectively pulls heat from the outside of your home, runs it through the condenser, and emits it into your space. ComfortUp’s ductless systems are rated to produce heat in outside temperatures down to or below 0°F; some as low as -22°F. In climates that encounter extreme cold, having a supplemental or backup heat source would be recommended. You will need a proper backup heating source, such as your furnace or boiler, when temperatures dip below 30 degrees Fahrenheit. With that being said, mini-split heaters can certainly provide some great supplemental warmth, especially during the fall and spring.  

How Mini-Splits Differ from Forced Air

If you’re not super familiar with typical forced-air cooling systems, such as central air, you may wonder how mini-splits differ. While both have an outdoor compressor, central air units rely on a , depending on the age and complexity of your home. With this kind of system, the temperature is controlled with a single thermostat, so there’s no room-by-room temperature control like you’d get with mini-splits.

Let ComfortUp Help with Your Mini-Split Job

While we always recommend partnering with an HVAC professional for installation, ComfortUp can assist you in the process of based on the configuration of your home, your budget, and your individual needs. We’re here to outfit you with the very best heating and cooling options around.


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