Thermocore T321S-H218-C T1 Series Ductless Mini Split : Cassette 18000 BTU Inverter Cooling Capacity along with a 18,000 BTU Heat Pump, this 1 TON Energy Star Ductless Split can cool or heat an area over 900 ft².  Advanced INVERTER DC Technology provides both energy efficient operation and low ambient operation start-ups. Additional features include auto-diagnostic functions and sleep mode / 24 hour timer.   Comes pre-charged with eco-friendly R410A
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9000 BTU inverter Split
Indoor Unit Indoor Unit Outdoor Unit warranty
 System Includes:
  • Indoor Unit - Air Handler - Cassette
  • Outdoor Unit - Compressor
  • Digital Multi-function LCD Remote Control)
  • Wall mounted thermostat included
  • Operates in Ambient Temps down to -13F!!
  • 15ft lineset/15ft wire included.
  • Extend linesets & wire using dropdown menu
  • 1 Yr Part, 5 yr Compressor Warranty >
  • 18000 BTU AC - Heat: 21 SEER - Cassette

    Price: $1421.45 Free Shipping
  • Select your choice of length for BTU: 
  • Select to add wire
    Features back to the top
    mini split features
    Top Line Features:
    • 21 SEER - 9.5 HSPF - ENERGY STAR  Energy Star
    • Most Energy Efficient 18k BTU Series on Market
    • Pre-Charged w/ Eco-friendly R410A Refrigerant
    • Dry-Mode removes moisture w/o affecting temp
    • Cross Flow Technology reduces noise output
    • Compatible with over 5 Filtration medias
    • Freon Leak Detection > Notification system
    • Operates in Ambient Temps down to -13F!!
    • Restart IC: Settings restored Following Outage
    • Follow-Me Function tracks Remote Location
    Energy Star benefits
    The particle filter or “pre-filter” removes dust and other air-borne pathogens before pushing the air through additional filtration medias and the refrigeration coil array.  This filter is washable and comes factory installed with every ductless air conditioner system.
    The open channel construction of the 3M High Air Flow (HAF) filter offers low initial airflow resistance, while its unique microstructure and electrostatic charge provides effective particle capture and retention. This translates into fewer filter change outs and reduced coil cleaning.  CLICK TO PURCHASE >>>
    The Vitamin C Filtration media releases Vitamin C into the air which softens skin and reduces stress among other therapeutic benefits.  A good choice for those wanting to add some invigoration to their indoor air environment.  Filter lasts over 2 years.  CLICK TO PURCHASE >>>
    The anti-microbial effect of silver ionic technology kills allergy causing bacteria by destroying the inner configuration elements of the cell body. The nano-silver attached to the filter screen constantly releases silver ions which directly eliminates and prohibits bacteria from replicating.  CLICK TO PURCHASE >>>
    Eliminates odors such as ammonia and deactivates harmful chemicals has such as formaldehyde.  By forming positive positions on the filter surface, Electrostatic Fiber traps small dust particles, smoke and pet dander to prevent allergic reactions and neutralize odor in the air.  CLICK TO PURCHASE >>>
    Specifications back to the top
    18000 BTU Indoor Unit specs CLICK FOR FULL SPEC SHEET
    Model Number T3-OS218-EC
    Capacity 18000 BTU
    Air Flow (Hi/M/Lo) 620/520/410 (m3/h)
    Power Supply 230 V / 60 Hz / 1Ph
    Noise Output (Hi/M/Lo) 50/47/43 dBA
    Liquid / Gas 1/4" x 1/2"
    Weight 45 lbs
    Body Dimensions (W x D x H) 25.47" x 25.47" x 2" inches
    Panel Dimensions (W x D x H) 22.44" × 22.44" × 10.24" inches
    Energy Star AHRI Energy Star
    21 SEER Toshiba Compressor
    Outdoor Unit (condenser) specs

    Model Number



    Toshiba (GMCC)


    R410A (Pre-Charged)/1900g

    Cooling Capacity

    18000 BTU

    Heating Capacity

    18000 BTU

    Air Flow

    1200/950/750 m3/h

    Power Supply

    208-230 V / 60 Hz, 1Ph

    Input Power

    1400W (cooling) / 1440W (heating)

    Input Current

    6.5A (Cooling) / 6.66A (Heating)







    Maximum Fuse


    Sound Level


    Moisture Removal

    1.7 L/hr

    Min Operating Temperature

    - 15 C / 5 F

    Net Weight

    102 Lbs


    33.27 x 12.60 x 27.56 in

    CLICK TO VIEW energy label >>>
    dc inverter
    DC Inverter Mini Split AC Heat Pump  

    DC Inverter Air Conditioners are the ultimate cooling and heating technology of the HVAC field.  They are called "DC inverter" because the alternative current (AC) is converted to Direct Current (DC) then, direct current inverted back to Alternative current with desired frequency. The current supplied through the wall outlet has fixed frequency which is 60 Hertz. Different frequencies supplied to the compressor will result in different running speeds of the compressor. Inverter control systems use Pulse Amplitude Modulation (PAM) that is the most advanced and energy efficient method of inverting the current.  DC Inverter AC's bear special compressors that their speed could be changed by increasing or decreasing the frequency of the supplied power.  Therefore, unlike conventional split Air Conditioners/Heat Pumps which cycle between on and off repeatedly, the DC Inverter control system will monitor the room temperature and adjust the compressor speed automatically.

    Conventional compressors turn on and off to maintain the room temperature at desired level.  This will result compressor to draw tremendous energy each time it starts up. This will also reduce the life-span of the compressor and other components that are turning on and off.  Once a conventional system is running, it runs at its maximum speed, consuming the maximum amount of energy in order to produce the maximum of cooling or heating to maintain the desired temperature.  The system will then cycle between on and off in an effort to maintain this temperature. When a DC Inverter compressor initially starts up, it runs with a higher speed to bring the room temperature to desired level rapidly, Once the set temperature is reached, it slows down and adjust its capacity just to counter the heat loss or heat gain of the building. Constant temperature is maintained.

    Inverter Split
    Available Accessories back to the top
    Our Thermocore systems ship via RL Carriers or similar LTL freight service out of Oak Park, Michigan and are palletized onto a single skid.  Transit time is usually between 4 to 6 business days from payment receipt depending on where you are geographically located.  Please provide a contact phone# upon checkout (to be used for delivery purposes only).  SOMEBODY MUST BE ON SITE TO ACCEPT / SIGN FOR Order.  Failure to provide valid contact# will delay order.  System comes with Free shipping - this includes delivery to any location within the Continental United States. We will ship to Canadian locations but we need to quote separately - please contact our offices.  Additional freight for Canadian registries is usually around $150. (import and duties may apply).
      RL Carriers
    Install Kit back to the top
     Install Kit Contents:
  • 15 Ft Flared Copper Tubing
  • 15 Ft Pipe Insulation
  • Drain Pipe (indoor)
  • Wall Bracket for Indoor Unit
  • Plastic Pipe Wrap
  •   Includes Install Kit
  • Installation and User Manual
  • Neoprene  Putty to Seal Holes

  •   Install Kit
    Installation Overview back to the top
    BASIC OVERVIEW: The installation of a ceiling cassette is much like that of a ductless mini split with the exception that instead of a wall mounted air handler, a ceiling cassette mounts in the ceiling usually as a flush mount or in a drop ceiling. The indoor unit (ceiling cassette) and outdoor unit (condenser) are connected to each other by means of refrigerant copper tubing and electrical cables that are routed through the ceiling and outside to the condenser outputs via a 2-3 inch hole. The compressor comes pre-charged with freon however, procedures such as conducting leak tests etc. are still important steps in ensuring proper functioning of a ceiling cassette system. Click for Installation Tip *Although the installation may seem easy to some, certain tools and experience is necessary to complete installation of a ceiling cassette system.  Click to Download Installation manual.  A certified HVAC technician must conduct / complete the installation to be eligible for product warranty. (See warranty details below > ) Installation Kit
    Ceiling Cassette Diagram
    Remote Controls back to the top
    *5 Year Compressor - 1 Year on all other Parts*  Registration card will be sent with unit, this card should be completed by an HVAC technician (installer).  Installation of a mini split must be completed by a licensed HVAC (Heating, ventilating, & air conditioning) company to ensure any issues encountered in the future are not due to improper installation / workmanship.  Even though mini split setup is below the expertise requirements of central AC systems, these are not "plug-n-play" units that can be properly installed without certain tools any prior HVAC - electrical knowledge.   The installation includes electrical, gas, and refrigerant connections and generally regulated by a multiple sets of laws, codes and guidelines, at the federal, state and local levels. The failure to properly install HVAC equipment can raise personal safety and performance concerns. Warranty service - troubleshooting is provided through the contractor / installer and will be upheld as long as policies are observed.  Once a non-defective unit is installed by a HVAC company, chances of anything going wrong are very slim and almost all contractors will guarantee there workmanship and provide future service free of charge (installation warranty).  If it was determined that the unit is not functioning due to a defect and needs to be replaced, the part will be sent free of charge up to 1 year from date of purchase or 5 years for the compressor. If you receive a damaged or defective product, a replacement unit will be sent out Free of cost.  Damaged / Defective product will be picked up and a brand new exchange will be shipped out. 1 YEAR PARTS WARRANTY CAN BE EXTENDED TO 2 YEARS FOR AN ADDITIONAL $72.00
    Mini Split ShippingTop
    Condenser Ground Stand

    - Provides Flat even surface
    - Avoids debris obstruction

    Price:  $73.00
    Click for more Info

    Lineset Extension (1/4 x 3/8)

    - Extend included 16 ft copper lineset to 25ft - 30ft - 40ft - 50ft
    Price:  $38.00 > $134.00
    Click for more Info

    Condenser Bracket

    - Mount your condenser at any height on an outdoor sidewall
    Price:  $46.00
    Click for more Info

    Micro-Pump II

    - Required when mounting air handler on Interior wall
    Price:  $172.00
    Click for more Info

    Electrical Wire Harness

    - 16/4 Electrical Wire Harness
    - For Extending Evap. Length

    Price:  $2.15 / ft
    Click for more Info

    Additional Remote Controls

    - Spare remote controls for the T1 Series Ductless System
    Price:  $42.00
    Click for more Info

    Filter Medias

    - Inserts into Filter Screen Slot
    - Choice of 4 Filtration Medias

    Price:  $10.00 - $14.00
    Click for more Info

    Wired Thermostat

    - Permanently Hard Mounts
    - Controls Settings w/ Remote

    Price:  $98.00
    Click for more Info

    Dotted Line
    mini split
    Call Thermospace at 855-382-8110
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