SplitAtlas

TOSOT / Multi Ultra Heat

TOSOT Multi Ultra Heat 18k R-32 208/230V 2-Zone Mini-Split

Certified capacity
18,000 BTU/h[2]
SEER2
21 SEER2[2]
Heating floor
-22 F[1]
Voltage
230 V[1]
Install path
Professional install

The TOSOT Multi Ultra Heat 2-zone runs two rooms from one 208/230V outdoor unit on R-32, ENERGY STAR certified and AHRI cold-climate designated, at a certified nominal SEER2 of 21 (EER2 12, HSPF2 10). That nominal is the all-non-ducted certified figure and depends on the heads you attach.

Heating is rated 18000 BTU at 47F, 17600 at 17F, and 13800 at 5F - it holds nearly full output at 17F before tapering at 5F. TOSOT is a value brand (part of the TOSOT/Gree family) sold on tosot.com, professionally installed and priced by quote.

2 zonesProfessional installCurrent

Refrigerant generation

R-32 - current-generation refrigerant

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Error Codes
TOSOT Multi Ultra Heat 2-Zone 18,000 BTU R-32 208/230V (TMH18D32MO)

Image: TOSOT

Data completeness: 97%
Last sourced
Jul 29, 2026

SplitAtlas score

8.5 / 10

Methodology
Cooling efficiencyBelow average

(21.0 SEER2) among 18k systems

Heating efficiencyAbove average

(10.0 HSPF2) among 18k systems

Cold-weather performanceAbove average

(76.7% heat retained at 5F; -22 F heating floor) among 18k systems

WarrantyAbove average

(10 yr parts / 10 yr compressor) across the catalogue

Feature setBelow average

(4 verified features) across the catalogue

Documentation & partsTop quartile

(8 manuals; spec sheet; 14 error-code rows) across the catalogue

Not evaluated

  • Installation accessibility — not applicable (professional install)N/A

    professional install - DIY-accessibility not applicable

  • Price-to-value — not evaluatedN/A

    This is a professionally installed, quote-only system, so we can't score its price. Get an installed quote to compare real cost.

    Get a quote

Key ratings

Rated cooling

18,000BTU/hNon-Ducted Indoor Units[2]

Rated heating

18,000BTU/hNon-Ducted Indoor Units[2]

Buyer review snapshot

Best for / skip if

Best for

  • 2-zone projects in the 18k outdoor capacity class.

Install difficulty

Complex professional install
  • Electrical: 230V; MCA 14.5 A; breaker/fuse 20 A.
  • Line set: connection type not sourced; precharged 33 ft; max 131 ft.
  • 2-zone condenser; indoor-head matching and branch layout are part of the job.

Alternatives

Availability and price context

We could not verify a current retail price for this model. These TOSOT/Cosmo multi-zone systems are professional-install equipment, so we link to contractor quotes rather than a retail price.

Source date

Model data sourced
Jul 29, 2026
Page reviewed
Jul 29, 2026
Source-backed records
5
Newest source retrieved
Jul 29, 2026

Warranty tiers

Warranty: 10 years parts and compressor as standard.

Review methodology

Model context

Install path
This is professional-install equipment; no verified current retail offer is attached.
Structured ratings
Certification: ENERGY STAR certified, ENERGY STAR cold-climate certified and AHRI cold-climate designated. Refrigerant: current low-GWP R-32. Minimum heating ambient: -22 F.

Strengths

  • Nearly flat 17F heat (17600 of 18000 BTU) before a deep-cold taper.
  • Certified nominal SEER2 21 / EER2 12 / HSPF2 10, ENERGY STAR certified on R-32.
  • Two zones from one outdoor unit and a single 208/230V circuit.

Weaknesses

  • Heating tapers at 5F (13800 BTU) - size for your coldest design day.
  • Two-zone total capacity is shared across both rooms.

Climate suitability

Minimum heating ambient
-22 F[1]
Rated heating at 5F
13,800 BTU/hNon-Ducted Indoor Units[2]
Rated heating at 17F
17,600 BTU/hNon-Ducted Indoor Units[2]
Rated heating at 47F
18,000 BTU/hNon-Ducted Indoor Units[2]

Specifications

Show
Manufacturer
TOSOT
Brand
TOSOT
Product line
Multi Ultra Heat
Model number
TMH18D32MO
Indoor unit model
Indoor heads are selected separately on a multi-zone system
Outdoor unit model
TMH18D32MO
Number of zones
2
Max indoor units
2 units[1]
Rated cooling capacity
18,000 BTU/hNon-Ducted Indoor Units[2]
Rated heating capacity
18,000 BTU/hNon-Ducted Indoor Units[2]
Voltage
230 V[1]
MCA
14.5 A[1]
Maximum fuse or breaker size
20 A[1]
Breaker needed
not published
SEER2
21 SEER2Non-Ducted Indoor Units[2]
EER2
12 EER2Non-Ducted Indoor Units[2]
HSPF2 (Region 4)
10 HSPF2Non-Ducted Indoor Units[2]
HSPF2 (Region 5)
Certified per indoor-unit combination, not per outdoor unit
COP
not published
COP at 47F
3.9 COP[1]
COP at 5F
2 COPNon-Ducted Indoor Units[2]
Minimum outdoor heating temperature
-22 F[1]
Minimum outdoor cooling temperature
-22 F[1]
Maximum outdoor temperature
118 F[1]
Indoor noise range
Indoor heads are selected separately on a multi-zone system
Outdoor noise rating
51 dBA[1]
Indoor weight
Indoor heads are selected separately on a multi-zone system
Outdoor weight
79 lb[1]
Refrigerant
R-32[2]
Refrigerant charge
32 oz[1]
Manufacturer coverage
not published
Line-set size
1/4 in x 2 liquid / 3/8 in x 2 suction
Included line-set length
Indoor heads are selected separately on a multi-zone system
Maximum line-set length
131 ft[1]
Max line set per indoor
66 ft[1]
Maximum elevation difference
49 ft[1]
Max height between indoor units
49 ft[1]
Wi-Fi support
Indoor heads are selected separately on a multi-zone system
Energy Star status
ENERGY STAR certified[3]
AHRI certification number
217994514Non-Ducted Indoor Units[2]
Warranty
Standard: 10 yr parts / 10 yr compressor (equipment sold and installed by licensed professionals in residential applications). TOSOT warranty information lists a standard 10-year compressor warranty and 10-year parts warranty for equipment sold and installed by licensed professionals in residential applications.
Install path
Professional install
Retail price
These TOSOT/Cosmo multi-zone systems are professional-install equipment, so we link to contractor quotes rather than a retail price.
Available retailers
not published
Manual links
AHRI public detail 217994514, ENERGY STAR exact AHRI rows 217994514, TMH18D32MO TOSOT Multi Ultra Heat submittal and official indoor submittals, TOSOT Multi Ultra Heat / TMH18D32MO current product page, Lead-gen/no-retail audit for TMH18D32MO, TOSOT Direct Mini Split AC Error Codes guide; TOSOT Direct FAQ Split Air Conditioner error code list; TOSOT official Multi Ultra Heat product page, TMH18D32MO TOSOT Multi Ultra Heat submittal, TOSOT warranty information
Specification sheet
TMH18D32MO TOSOT Multi Ultra Heat submittal
Last sourced date
Jul 29, 2026

Compatible indoor units

This is an outdoor unit. You choose its indoor heads separately - up to the maximum this condenser supports - and you can mix room sizes and styles across the zones. The models below are the heads this unit is documented to pair with.

  • Ceiling cassette air handlers

    9k, 12k, 18k, 24k

    Model numbers
    • 9k: TKH09D32AI
    • 9k: TLH09D32AI
    • 12k: TKH12D32AI
    • 12k: TLH12D32AI
    • 18k: TKH18D32AI
    • 18k: TLH18D32AI
    • 24k: TKH24D32AI

  • Ducted concealed air handlers

    9k, 12k, 18k, 24k

    Model numbers
    • 9k: TFH09D32AI
    • 12k: TFH12D32AI
    • 18k: TFH18D32AI
    • 24k: TFH24D32AI

  • Ducted multi-position air handlers

    12k, 18k, 24k

    Model numbers
    • 12k: TAH12D32AI
    • 18k: TAH18D32AI
    • 24k: TAH24D32AI

  • Floor console air handlers

    9k, 12k, 18k

    Model numbers
    • 9k: TEH09D32AI
    • 12k: TEH12D32AI
    • 18k: TEH18D32AI

  • Wall-mounted air handlers

    7k, 9k, 12k, 18k, 24k

    Model numbers
    • 7k: TWH07CD32AI
    • 9k: TWH09CD32AI
    • 9k: TWH09KD32AI
    • 9k: TWH09PD32AI
    • 12k: TWH12CD32AI
    • 12k: TWH12KD32AI
    • 12k: TWH12PD32AI
    • 18k: TWH18CD32AI
    • 18k: TWH18KD32AI
    • 18k: TWH18PD32AI
    • 24k: TWH24CD32AI
    • 24k: TWH24KD32AI
    • 24k: TWH24PD32AI

Sizing note: do not just add up the rooms. Multi-zone condensers have a maximum total connected capacity, and connecting more head capacity than the unit is rated for is a common installer mistake that hurts efficiency and comfort. Match total head capacity to the condenser's rating.

Electrical requirements

Show
Voltage
230 V[1]
Voltage range
208/230V[1]
Phase
1[1]
Frequency
60 Hz[1]
MCA
14.5 A[1]
Breaker needed
not published
Maximum breaker size
20 A[1]
Maximum fuse size
20 A[1]
Maximum cooling current
not published
Maximum heating current
not published
Manufacturer wire notes
not published

Installation considerations

Show
Liquid line
1/4 in x 2[1]
Suction line
3/8 in x 2[1]
Line connection type
not published
Precharged length
33 ft[1]
Included line-set length
Indoor heads are selected separately on a multi-zone system
Maximum line-set length
131 ft[1]
Max line set per indoor
66 ft[1]
Max height between indoor units
49 ft[1]
Indoor dimensions
Indoor heads are selected separately on a multi-zone system
Outdoor dimensions
32-23/64 x 13-55/64 x 21-21/32 in[1]
Indoor weight
Indoor heads are selected separately on a multi-zone system
Outdoor weight
79 lb[1]
Drain size
not published

Related systems and guides

Frequently asked questions

Can I install the TOSOT Multi Ultra Heat 2-Zone 18,000 BTU R-32 208/230V (TMH18D32MO) myself, or do I need a pro?
TOSOT Multi Ultra Heat 2-Zone 18,000 BTU R-32 208/230V (TMH18D32MO) is built for professional installation: the line set must be flared, evacuated, and charged, which requires EPA-certified refrigerant handling. Installing it outside the manufacturer's requirements can void the warranty, so budget for a qualified HVAC installer.
Will the TOSOT Multi Ultra Heat 2-Zone 18,000 BTU R-32 208/230V (TMH18D32MO) keep heating in a cold winter?
The manufacturer publishes 13,800 BTU/h of heating output at 5F. Rated heating operation extends down to -22 F. Certified heating efficiency is 10 HSPF2. Match those numbers against your climate's design temperature - in cold regions, output at 5F matters far more than the nameplate capacity measured at 47F.
What electrical circuit does the TOSOT Multi Ultra Heat 2-Zone 18,000 BTU R-32 208/230V (TMH18D32MO) need?
Published electrical requirements: 230 V voltage, 14.5 A minimum circuit ampacity, and 20 A maximum breaker or fuse sizing. Confirm the final circuit against the unit nameplate and local code with a licensed electrician.
How far can the outdoor unit be from the indoor head?
The published maximum line-set length is 131 ft, and the included line set comes pre-charged for 33 ft. Longer runs than the included set allows typically mean added refrigerant and a pro visit, so measure the planned routing before ordering.
What warranty does the TOSOT Multi Ultra Heat 2-Zone 18,000 BTU R-32 208/230V (TMH18D32MO) carry?
The manufacturer publishes these warranty tiers: Standard: 10 yr parts / 10 yr compressor (equipment sold and installed by licensed professionals in residential applications). Registration requirements and proof of qualified installation commonly affect coverage, so read the warranty terms before install day.

Data sources

Show
  1. TOSOT: TMH18D32MO TOSOT Multi Ultra Heat submittalSourced - manufacturer technical document

    Covers Frequency, electrical_spec.guaranteed_voltage_range, Maximum breaker size, Maximum fuse size, Minimum circuit ampacity, Phase and more

  2. AHRI certificate #217994514 - search the AHRI DirectorySourced - AHRI directory

    Covers AHRI certification number, performance_spec.cold_climate_designation, Rated cooling capacity, COP at 5F, EER2, Rated heating capacity and more

  3. ENERGY STAR: ENERGY STAR exact row check for AHRI 215735288Sourced - Energy Star listing

    Covers performance_spec.energy_star_cold_climate, Energy Star status

  4. TOSOT: TOSOT Multi Ultra Heat / TMH60D32MO current product evidenceSourced - manufacturer product page

    Covers product_line.name

  5. TOSOT: TOSOT warranty informationSourced - manufacturer product page

    Covers Legacy compressor warranty value, Legacy warranty value, Standard compressor warranty, Standard warranty conditions, Standard parts warranty, Warranty notes

  6. TMH18D32MO TOSOT Multi Ultra Heat submittal and official indoor submittalsSourced - manual

    Covers Manual links

Last updated

Jul 29, 2026