Whether you’re looking to add air conditioning to an addition, cool a hot spot in your house, or update your dated HVAC system, you’ve likely stumbled upon something called a “mini split.” Unless you’re well-versed in HVAC terminology, it is not entirely obvious what a mini-split HVAC unit is.
We explain what a mini split is, how it differs from traditional central air systems, and whether it’s the right choice for cooling your home.
What Is a Mini Split?
A mini split, also known as a ductless mini split, is an HVAC system that utilizes an indoor unit, an outdoor unit, refrigerant lines, and electrical wiring, all without the need for traditional ductwork.
The absence of ductwork makes mini splits a versatile option for older homes and areas with limited access. Additionally, their simple installation and DIY-friendly models make mini splits an accessible option for experienced DIYers.
While mini-split HVAC systems aren’t typically a viable option for whole-home heating and cooling, they can be great for zoned systems or as supplemental units for large homes with multiple rooms and homes with new additions.
How Mini Splits Work
Ductless mini-splits work by transferring heat via the refrigerant lines. When cooling, the heat is transferred and released at the outside condenser unit. The coolant is then recirculated to the inside unit, where cool air is blown from the wall-mounted air handler.
When heating, a reversing valve allows the outside unit to pull heat from the outside air even when it’s cold outside (within reason), and then release warm air from the wall-mounted air handler.
Difference Between Mini Split vs. Central Air
The biggest difference between a mini split system and a traditional central air system is the lack of ductwork.
A central air system gets its name from the unit’s central location. The air is conditioned at the unit and then distributed throughout the home via ductwork in the floors, walls, and ceilings.
Because a ductless mini-split has no ductwork, it only releases air directly from the unit, which is why it is most effective in zoned systems, isolated rooms, ADUs, and similar situations. This design makes mini-splits highly efficient for targeted temperature control, but less than ideal for large spaces or homes with multiple rooms and zones.
The Best Rooms and Spaces for Mini Splits
- Attics and basements: These spaces are notorious for temperature fluctuations because they can be challenging to heat and cool, especially if they lack insulation or adequate ductwork for a central air system.
- Bedrooms: Many people prefer their bedrooms to be cooler than the rest of their homes. Rather than cranking down the AC and wasting money cooling the entire house, a mini-split lets you tailor your bedroom’s temperature to your liking.
- Distant rooms: In larger homes or those with sprawling layouts, rooms far from the HVAC unit may struggle to maintain an ideal temperature. Installing a mini split system provides more control over these types of spaces.
- Garages and sheds: These days, garages and sheds serve a wide range of purposes, from home gyms to short-term rental units. Mini splits can enhance the comfort of these often-overlooked spaces during central air system installation.
- Room additions: When adding onto a home, running ductwork from an existing central air system can be difficult and expensive. Additionally, the extra square footage may be too much for your existing HVAC system to handle.
Mini Split: Pros and Cons
To help you decide if a mini split is the right option for your home’s HVAC system, we’ve identified the pros and cons.
Pros
- Easy installation: Compared to a traditional HVAC system, a mini-split system is straightforward to install and requires no ductwork, which can be especially challenging in older homes.
- Zoned temperature control: A central HVAC system has its perks, but it can be limited for larger homes with multiple zones. These areas can benefit from mini-split installation, which gives more control over the climate than ever before.
- Energy savings: In addition to being highly efficient, mini split HVAC systems conserve energy by eliminating ductwork, which prevents the typical duct losses associated with traditional HVAC systems.
Cons
- Higher upfront cost: Mini-split systems are relatively expensive, with an average cost of $3,000.1 However, experienced DIYers can save money by installing the unit themselves, though specific “DIY-friendly” mini-split systems are recommended in this case.
- Unsightly inside unit: If your goal is to keep your HVAC system as discreet as possible, a mini-split isn’t your best option. While traditional HVAC systems feature nothing more than covered vents and returns in the living space, the indoor unit of a mini-split is mounted directly on the wall.
- Limited coverage: While a mini-splits design makes it ideal for isolated living spaces, small additions, and multi-zone floor plans, it won’t perform well if you intend it to heat or cool large areas of your home.
