Mini Split Indoor Unit Buying Guide

When refining a space or tackling larger, more complex HVAC projects, selecting the right indoor mini-split unit is critical. Mini-splits offer efficient, ductless climate control, but the perfect unit depends entirely on your home's layout and your aesthetic preferences.

Types of Mini Split Indoor Units

Each indoor unit style offers distinct advantages depending on your space, installation requirements, and design preferences.

Wall-Mounted Units

Wall-mounted indoor mini split units are the most common, cost-effective, and efficient type of indoor unit

They are also the cheapest, easiest to install, and offer the widest variety of sizes and efficiency ratings, ranging from 6,000 BTU/hr up to 36,000 BTU/hr and work for both single-zone and multi-zone systems. Some manufacturers even offer discrete, higher-end designs to match your décor.

Wall-mounted units are typically mounted near the ceiling on an exterior wall, requiring about a 3-inch penetration for lines and wires. Remember that they are visible, and rooms with narrow walls, high windows, or other obstacles may not have the space required for the unit (usually 30" to 42" wide).

Ceiling Cassette Units

Ceiling cassette indoor mini-split units mount within the ceiling structure itself, offering a nearly invisible heating and cooling solution while retaining the performance benefits of a ductless system.

These units are clean, discreet, and ideal for maintaining a seamless aesthetic. They usually include lift pumps to handle condensation removal, and some models can even supply fresh outside air or condition a small adjacent space, like a bathroom, with a short duct branch.

Ceiling cassette units are best suited for T-bar/drop ceilings or conventional joist and drywall ceilings where there is sufficient vertical clearance (typically 10" to 14"). Available in 36"x36" or 24"x24" sizes, these units require adequate space above the ceiling for installation.

Concealed Duct Units

Concealed duct indoor mini-split units are a compromise between traditional central forced air and ductless mini-splits. They sacrifice some efficiency for maximum concealment and the ability to condition multiple spaces.

The unit itself is installed completely out of view (e.g., in a closet, conditioned attic, or crawlspace), leaving only the visible grilles in the conditioned space. You can choose a grille design to fit your home's décor. They are ideal when wall units are too obtrusive and ceiling cassettes are not feasible. They can also supply two small, closely situated rooms from a single unit.

Concealed duct units use short duct runs to deliver air where needed, and a separate connection to pull return air back to the unit.

Because the thermostat is only placed in one of the rooms, accurate temperature control in the second room is often difficult. It’s a small sacrifice in efficiency due to the ductwork.

Other Specialized Options

While the three types above serve most applications, there are also specialized indoor units for specific needs:

• Suspended Indoor Units
• Floor-Mounted Indoor Units
• Air-Handler Units

Once you've matched the unit type to your space and aesthetic goals, you can proceed to sizing and selecting the appropriate mini-split accessories.

Explore Ferguson Home's selection of mini-split indoor units to find the perfect fit for your project.