Mini Split Indoor Units

AC Direct stocks mini-split indoor units from Goodman, Daikin, Mitsubishi, and ACiQ - wall-mounted air handlers, ceiling cassettes, and floor console units available as standalone components to pair with your existing outdoor condenser or as part of a new complete ductless mini split system. Every order ships free on orders of $1,500+ with a 10-year factory warranty and expert compatibility support available seven days a week.

If you're replacing a single indoor air handler or adding a zone to an existing multi-zone system, the most important step is confirming that the indoor unit you choose is compatible with your outdoor condenser - matching brand, refrigerant type, and BTU capacity. Our HVAC specialists can confirm compatibility before you order. Call 866-862-8922 or use the free Mini Split BTU Sizing Calculator to verify your zone requirements.

Mini Split Air Handler Types

Mini-split indoor units come in four main configurations, each suited to different room layouts, architectural constraints, and airflow requirements.

Wall-mounted units are the most widely installed configuration and are stocked in the broadest range of BTU capacities. Ceiling cassettes and floor consoles are available for spaces where wall mounting isn't practical. For applications requiring completely concealed units, concealed ducted air handlers connect to short duct runs while maintaining the efficiency of a ductless refrigerant system.

Choosing the Right BTU Capacity

Each mini split indoor air unit must be sized to match the room it conditions. An undersized air handler runs continuously without reaching the set temperature- an oversized unit short-cycles, causing humidity problems and increased wear. Use the table below as a starting point, then adjust for ceilings above 8 ft, high-sun exposure, and poor insulation. For a precise recommendation, use AC Direct's free Mini Split BTU Sizing Calculator.

A 12,000 BTU mini split indoor unit is the most common choice for bedrooms and medium rooms up to 550 sq ft. For small rooms under 250 sq ft - a home office, nursery, or single bedroom - a 9,000 BTU air handler typically delivers the most efficient performance without over-conditioning the space.

Compatibility: Matching Indoor to Outdoor Units

A mini-split indoor unit only functions correctly when it is paired with a compatible outdoor condenser. Before ordering a standalone air handler, verify the following five compatibility factors.

If you are unsure whether an indoor unit matches your existing outdoor system, call 866-862-8922 or start a live chat - our team will cross-reference your outdoor unit's model number against available indoor heads. You'll also need refrigerant line sets and ductless accessories for a complete installation.

Benefits of a Ductless Mini Split Indoor Unit

Replacing a window unit or central air register with a dedicated mini-split indoor air unit delivers measurable improvements in comfort, efficiency, and noise levels. Wall-mounted air handlers operate at 19–26 dB at low fan speed - near-silent compared to the 50–65 dB of a typical window unit. Because each air handler conditions only its assigned zone, you stop paying to cool or heat unoccupied rooms.

Energy-efficient mini split indoor units with inverter technology modulate their output continuously rather than cycling fully on and off - the same principle that makes inverter-driven appliances cheaper to run. Combined with the elimination of duct losses (20–30% of energy in central systems), a ductless air handler typically delivers a lower operating cost per square foot than any ducted alternative.

For rooms where existing window units or portable ACs are the only option, a wall-mounted mini split indoor unit is particularly well-suited - it occupies no floor space, doesn't block window light, and can be installed in apartments and rental properties with minimal structural modification. Many models also include Wi-Fi connectivity and smart controls compatible with home automation platforms. See ductless accessories for compatible thermostats and control modules.

Why Buy from AC Direct?

As America's leading discount HVAC supplier since 2001, AC Direct sells directly to homeowners and contractors, cutting out the dealer markup that typically adds 20–40% to HVAC component pricing.

Shop Mini Split Indoor Units

Browse all indoor air handlers above. Filter by BTU capacity, unit type, and brand to narrow your selection. Every product page includes compatibility information, technical specifications, and customer reviews. If you need a complete system rather than a standalone component, browse single-zone mini split systems or our full range of multi-zone ductless systems for pre-matched outdoor and indoor unit combinations.

For commercial applications requiring multiple zones across a larger footprint, consider commercial mini-split systems. 

Frequently Asked Questions

1. What is a mini split indoor unit?

A mini-split indoor unit, also called a mini-split air handler or mini-split indoor air unit, is the interior component of a ductless air conditioning system. It receives refrigerant from the outdoor condenser via slim-line sets, conditions the air in its zone, and delivers it directly to the room through an integrated fan - with no ductwork required. Each indoor unit operates independently with its own thermostat, enabling room-by-room temperature control.

2. What are the benefits of a mini split indoor unit?

Mini split indoor units deliver zone-by-zone temperature control, eliminate duct losses (typically 20–30% of energy in central systems), and operate at 19–26 dB - near-silent compared to window units or central air registers. Inverter-driven models modulate output continuously for stable temperatures and lower energy consumption. Units are compact, require only small wall penetrations for line sets, and are suitable for rooms where window or portable units are the only existing alternative.

3. How do I install a mini split indoor unit?

Installation involves mounting the indoor air handler on the wall (or ceiling for cassette types), drilling a small access hole for refrigerant line sets and low-voltage communication wiring, connecting the line set to the outdoor condenser, and commissioning the system with a licensed HVAC technician for refrigerant charging. Refrigerant handling requires EPA 608 certification by law. Most single-zone installations are completed in half a day by a qualified contractor.

4. What size mini split indoor unit do I need?

Sizing is primarily determined by room square footage. A 9,000 BTU air handler suits rooms up to 250 sq ft- a 12,000 BTU unit covers 250–550 sq ft- and 18,000–24,000 BTU units handle larger open-plan areas. Adjust upward for high ceilings, poor insulation, or south-facing rooms with significant solar gain. Use AC Direct's free Mini Split BTU Sizing Calculator for a precise recommendation, or call 866-862-8922 for a personalised assessment.

5. Can a mini split indoor unit be used for heating?

Yes - when paired with an outdoor condenser for a heat pump, the indoor air handler delivers both cooling and heating by reversing the refrigerant cycle. The outdoor unit extracts heat from outdoor air and circulates it into the air handler. Advanced heat pump systems operate efficiently down to −13°F outdoor temperature, making them a viable year-round heating solution in most US climates without a separate furnace.

6. What is the difference between a mini split and central air?

Central air conditioning circulates conditioned air through a shared duct network, losing 20–30% of energy to duct leakage and providing no per-room temperature control. A ductless mini split delivers conditioned air directly to each zone via individual air handlers, eliminating duct losses. Installation is significantly less invasive - requiring only small wall penetrations for line sets rather than duct runs through floors, walls, and ceilings. Mini splits are the practical choice for homes without existing ductwork, room additions, and buildings where per-room control is a priority.

7. Are mini split indoor units compatible with any outdoor condenser?

No. Indoor air handlers must be matched to a compatible outdoor condenser by brand, refrigerant type (R-410A, R-32, or R-454 B), and BTU capacity. Mitsubishi indoor heads require Mitsubishi outdoor units- Daikin and Goodman systems are brand-specific as well. Mixing incompatible brands or refrigerants voids the warranty and risks system damage. AC Direct's team can cross-reference your outdoor unit model number to confirm which indoor units are compatible - call 866-862-8922 before ordering.

8. What maintenance does a mini split indoor unit require?

Primary maintenance tasks are: cleaning or replacing the washable filter every 4–6 weeks during active use, wiping down the unit's casing and louvres, and having a licensed HVAC technician inspect the refrigerant level, electrical connections, and drain line annually. A clean filter maintains airflow efficiency and prevents the indoor air handler from overworking. Annual professional servicing extends the unit's lifespan - with proper care, a mini-split indoor unit typically lasts 15–20 years.

9. Does AC Direct offer financing for mini split indoor units?

Yes. AC Direct offers EZ Pay financing with no credit check required and zero-interest options available at checkout. Both options are accessible to buyers with no credit history or poor credit. All indoor units also ship free on orders over $1,500 and include a 10-year factory-backed warranty. Goodman and Daikin indoor units are additionally covered by AC Direct's 125% Low Price Guarantee - if you find a lower price, AC Direct refunds 125% of the difference.