Ductless mini-split systems have revolutionized HVAC, offering flexible solutions where traditional systems fall short. Here's what you need to know.
What Is a Mini-Split?
A mini-split consists of an outdoor compressor/condenser unit connected to one or more indoor air handlers. Refrigerant lines (not ductwork) connect the components through a small hole in the wall.
Advantages
No Ductwork Required Perfect for: - Older homes without existing ducts - Room additions - Converted garages - Accessory dwelling units (ADUs)
Installing ductwork can cost $10,000-$20,000; mini-splits eliminate this expense.
Zone Control Each indoor unit has its own thermostat. Cool or heat only occupied rooms instead of the whole house.
Energy Efficiency Mini-splits avoid duct losses (which waste 20-30% of energy in typical systems). Many models achieve 20+ SEER ratings.
Quiet Operation Indoor units operate at 20-40 decibels—quieter than a library.
Flexible Installation Indoor units mount on walls, ceilings, or floors. Multiple styles suit different aesthetics.
Both Heating and Cooling Heat pump models provide year-round comfort from a single system.
Disadvantages
Aesthetics Indoor units are visible, which some homeowners dislike. Concealed ceiling cassettes offer a solution but cost more.
Higher Upfront Cost Single-zone systems start around $3,000-$5,000 installed. Multi-zone systems cost $5,000-$15,000 depending on capacity.
Not Ideal for Whole-House While multi-zone systems can condition an entire home, costs can exceed traditional HVAC for larger homes with existing ductwork.
Maintenance Requirements Indoor units need regular filter cleaning and occasional professional maintenance for each head.
Best Applications
Mini-splits excel for:
- Room additions without extending ductwork
- Hot or cold rooms that central HVAC doesn't reach well
- Sunrooms and three-season rooms
- Garages and workshops
- Home offices needing independent control
- ADUs and in-law suites
- Older homes without ductwork
- Supplementing window units with a permanent, efficient solution
Sizing Considerations
Mini-splits are sized in BTUs. General guidelines:
- 150-350 sq ft: 9,000 BTU
- 350-500 sq ft: 12,000 BTU
- 500-700 sq ft: 18,000 BTU
- 700-1,000 sq ft: 24,000 BTU
Professional sizing calculations account for insulation, windows, sun exposure, and climate.
Top Brands
- Mitsubishi: Industry leader, Hyper-Heating technology
- Fujitsu: Excellent value, strong performance
- Daikin: Japanese innovation, owns Goodman
- LG: Smart home integration, design options
Installation Considerations
Mini-split installation requires: - Mounting indoor and outdoor units - Running refrigerant lines - Electrical connections - Proper charging and testing
While DIY kits exist, professional installation ensures proper sizing, placement, and warranty coverage.
For the right application, mini-splits offer unmatched flexibility and efficiency.