Ductless Mini Split Systems
Efficient, flexible, and whisper-quiet heating and cooling without the need for ductwork.
How Ductless Mini Splits Work
A ductless mini split system consists of two main components: a compact outdoor compressor/condenser unit and one or more indoor air-handling units. These are connected by a small conduit that houses the refrigerant tubing, power cable, and condensate drain — requiring only a 3-inch hole through your wall.
In cooling mode, the indoor unit absorbs heat from your room air and transfers it via refrigerant to the outdoor unit, which releases it outside. In heating mode, the process reverses: the outdoor unit extracts heat from the outdoor air (even in cold temperatures) and delivers it inside. This heat pump technology makes mini splits remarkably efficient because they move heat rather than generate it.
The inverter-driven compressor in modern mini splits continuously adjusts its speed to match the precise heating or cooling demand. Instead of cycling on and off like traditional systems, it runs continuously at the lowest speed needed, maintaining your exact set temperature with minimal energy use and virtually no noise.
Benefits of Mini Split Systems
Ductless mini splits offer advantages that conventional HVAC systems simply cannot match.
Zone Control
Individual Room Temperature Control
Each indoor unit operates independently with its own thermostat, allowing you to set different temperatures in different rooms. Heat the living room to 72 degrees while keeping the bedroom at 68 degrees. Only condition the rooms you’re actually using, and eliminate household thermostat wars for good.
No Ductwork
No Ductwork Required
Mini splits require only a small 3-inch hole through the wall to connect the indoor and outdoor units. There’s no need to install, maintain, or lose energy through ductwork. This makes them the ideal solution for older homes without ducts, room additions, converted garages, and any space where running ductwork would be impractical or expensive.
Efficiency
Modern mini splits achieve SEER2 ratings up to 33.1, making them among the most efficient HVAC systems available. By eliminating duct losses (which account for up to 30% of energy waste in conventional systems) and using inverter-driven compressors, mini splits can reduce your heating and cooling costs by 30-50%.
Flexibility
Versatile Installation Options
Indoor units are available in wall-mounted, ceiling cassette, floor-standing, and concealed-duct configurations. This flexibility allows you to choose the style that best fits your space, aesthetics, and comfort preferences. Most installations can be completed in a single day with minimal disruption.
Air Quality
Improved Indoor Air Quality
Without ductwork to collect dust, allergens, and mold, mini splits deliver cleaner air to every room. Advanced multi-stage filtration systems in the indoor units capture particulates, allergens, and odors. Many models include washable filters that are easy to maintain.
Quiet
Whisper-Quiet Operation
Indoor units operate as low as 19 dB, quieter than a library. You’ll barely know the system is running. Outdoor units are equally subdued, making mini splits the perfect choice for bedrooms, nurseries, home offices, and noise-sensitive environments where traditional HVAC noise would be disruptive.
Single-Zone vs. Multi-Zone Systems
Choose the configuration that best fits your space and comfort needs.
Single-Zone Mini Splits
A single-zone system pairs one outdoor unit with one indoor unit, providing dedicated heating and cooling for a single room or area. This is the most affordable and straightforward mini split configuration.
Best Applications:
- Individual bedrooms or home offices
- Garage conversions and workshops
- Sunrooms and enclosed porches
- Room additions and ADUs
- Server rooms and specialty spaces
- Supplementing an existing system for problem rooms
Capacity Range:
9,000 to 36,000 BTU, suitable for rooms from 250 to 1,500 square feet.
Multi-Zone Mini Splits
A multi-zone system connects a single outdoor unit to multiple indoor units (typically 2 to 8), each independently controlled. This allows whole-home comfort from a single outdoor unit, with different temperatures in every room.
Best Applications:
- Whole-home heating and cooling without ductwork
- Multi-story homes with uneven temperatures
- Homes with multiple comfort zones needed
- Open-concept floor plans with distinct living areas
- In-law suites and guest houses
- Replacing aging central systems room-by-room
Capacity Range:
9,000 to 36,000 BTU, suitable for rooms from 250 to 1,500 square feet.
Our Mini Split Installation Process
Allison Air Comfort Solutions follows a thorough, professional installation process to ensure your mini split system delivers optimal performance from day one.
Step 1: In-Home Consultation
We visit your home to assess your space, discuss your comfort goals, and perform a Manual J load calculation to determine the exact capacity needed. We’ll recommend the best system configuration, brand, and indoor unit styles for your situation.
Step 2: System Design & Proposal
We prepare a detailed proposal including equipment specifications, installation plan, pricing, and available rebates. We’ll walk you through every option and answer all your questions before you commit.
Step 3: Professional Installation
Our certified technicians install your system with meticulous attention to detail. This includes mounting indoor units, placing the outdoor unit, running the refrigerant line set, making electrical connections, and performing a vacuum and pressure test on the refrigerant circuit. Most single-zone installations are completed in one day.
Step 4: Commissioning & Testing
After installation, we charge the system with the precise amount of refrigerant, test all operating modes, verify airflow and temperature performance, and calibrate the thermostat. We won’t leave until your system is running perfectly.
Step 5: Walkthrough & Training
We give you a complete walkthrough of your new system, including remote control operation, smart app setup, filter maintenance, and recommended service schedules. We’re always just a phone call away if you have questions later.
Best Applications for Mini Splits
Mini splits are the ideal solution for a wide range of heating and cooling challenges.
Additions
Room Additions & ADUs
Adding a room to your home? Extending your existing ductwork is often impractical and expensive. A mini split provides dedicated heating and cooling for the new space with a simple, clean installation that doesn’t burden your existing HVAC system.
Garages
Converted Garages & Workshops
Garages converted to living spaces, home gyms, or workshops are notoriously difficult to heat and cool. Mini splits deliver powerful, efficient climate control to these spaces without running ductwork from the main house.
Older Homes
Converted Garages & Workshops
Garages converted to living spaces, home gyms, or workshops are notoriously difficult to heat and cool. Mini splits deliver powerful, efficient climate control to these spaces without running ductwork from the main house.
Hot/Cold Rooms
Problem Rooms & Hot Spots
That one room that’s always too hot in summer or too cold in winter? A single-zone mini split solves the problem by providing independent temperature control that your central system can’t achieve. It’s the most effective fix for rooms at the end of long duct runs or over unconditioned spaces.
Sunrooms
Sunrooms & Enclosed Porches
Sunrooms and three-season porches experience extreme temperature swings due to their large glass areas. A mini split with heat pump capability transforms these spaces into comfortable, year-round living areas with precise climate control.
Offices
Home Offices & Studios
Remote work demands a comfortable environment. Mini splits provide ultra-quiet, draft-free comfort that’s perfect for home offices, music studios, and creative workspaces. Independent zone control means you can keep your office at the ideal temperature without heating or cooling the entire house.
Mini Split Brands We Install
We carry the industry’s most trusted mini split brands, each with unique strengths.
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Feature
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Mitsubishi Electric
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LG
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Bosch
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|---|---|---|---|
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Max SEER2
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Up to 33.1
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Up to 27.5
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Up to 22.0
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Indoor Noise Level
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19 dB
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19 dB
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20 dB
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Cold Climate Heating
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H2i: down to -13°F
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LGRED°: down to -13°F
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Down to -4°F
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Multi-Zone Capacity
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Up to 8 zones
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Up to 8 zones
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Up to 5 zones
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Smart Control
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kumo cloud app
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LG ThinQ app
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Built-in Wi-Fi
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Indoor Unit Styles
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Wall, ceiling, floor, ducted
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Wall, ceiling, floor, ducted
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Wall-mounted
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Compressor Warranty
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12 years
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10 years
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7 years
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Best For
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Premium efficiency & variety
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Smart features & value
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Budget-friendly reliability
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Mini Split Installation Gallery
Real mini split installations by Allison Air across the Bay Area
Mini Split Install - San Jose
Mitsubishi Electric inverter wall-mounted unit installed above a window in a residential living space. Clean installation with minimal visual impact.
Ceiling Cassette - New Build
Flush-mounted ceiling cassette unit installed during new construction. Provides 360-degree airflow while integrating seamlessly with the ceiling.
Ductless Mini Split - Sunnyvale
Mitsubishi Electric inverter unit installed near the ceiling in a room with panel ceiling tiles. Quiet, efficient zone-based heating and cooling.
Ready for Ductless Comfort?
Contact Allison Air Comfort Solutions for a free in-home consultation and mini split installation quote.