SplitAtlas

Mitsubishi Electric / M-Series FX Deluxe Hyper-Heat

Mitsubishi M-Series FX Deluxe 12k HZ R-454B 208/230V Mini-Split

Certified capacity
12,000 BTU/h[4]
SEER2
29.9 SEER2[4]
Heating floor
-22 F[1]
Voltage
208/230V[1]
Install path
Professional install

The M-Series FX 12k brings the flagship Hyper-Heat formula to 1 ton: SEER2 29.9, EER2 15.4, HSPF2 12.4, with 13,200 BTU certified at 47F and 16,200 BTU at 5F. Efficiency steps down from the 6k and 9k models - normal as capacity grows - and it runs on current R-454B.

1 zoneProfessional installCurrent

Refrigerant generation

R-454B - current-generation refrigerant

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Error Codes
Mitsubishi Electric M-Series FX Deluxe Hyper-Heat 12,000 BTU R-454B 208/230V (MSZ-FX12NL / MUZ-FX12NLHZ)

Image: Mitsubishi Electric

Data completeness: 95%
Last sourced
Jul 23, 2026

SplitAtlas score

9.3 / 10

Methodology
Cooling efficiencyTop 10%

(29.9 SEER2) among 12k systems

Heating efficiencyTop 10%

(12.4 HSPF2) among 12k systems

Cold-weather performanceTop 10%

(5F certified capacity: 100% of the 47F rating; -22 F heating floor) among 12k systems

NoiseTop quartile

(20 dBA indoor min / 51 dBA outdoor) among 12k systems

WarrantyTop quartile

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

Feature setBottom quartile

(2 verified features) across the catalogue

Documentation & partsTop quartile

(9 manuals; spec sheet; parts channel) 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

12,000BTU/h[4]

Rated heating

13,200BTU/h[4]

Buyer review snapshot

Best for / skip if

Best for

  • Top efficiency shortlists; SEER2 is 29.9.

Install difficulty

Professional install
  • Electrical: 208/230V; MCA 14 A; breaker/fuse 15 A.
  • Line set: connection type not sourced; precharged 25 ft; max 65 ft.

Availability and price context

This system needs a professional install, so its real price is an installed quote that depends on your home. We don't link to a listing for this exact model; get installation quotes to price it.

Source date

Model data sourced
Jul 23, 2026
Page reviewed
Jul 23, 2026
Source-backed records
6
Newest source retrieved
Sep 12, 2026

Warranty tiers

Base
5 yr parts / 7 yr compressor - licensed HVAC contractor installation
Registered
10 yr parts / 10 yr compressor - owner-occupied residence registered within 90 days of installation
Program
12 yr parts / 12 yr compressor - owner-occupied residence installed and registered by a Diamond Contractor within 90 days

The score uses Registered. Additional published terms are shown for reference and not counted in the score.

Review methodology

Model context

Structured ratings
Certification: ENERGY STAR certified and AHRI cold-climate designated. Refrigerant: current low-GWP R-454B. Minimum heating ambient: -22 F.

Strengths

  • SEER2 29.9 with HSPF2 12.4 - excellent efficiency and seasonal heating for a 1-ton system.
  • True Hyper-Heat: 16,200 BTU at 5F, rated for sub-zero operation.
  • Current R-454B refrigerant; Mitsubishi dealer support and reliability reputation.

Weaknesses

  • Premium price and professional dealer installation required.
  • Efficiency is below the smaller FX models - the SEER2 premium is largest at 6k/9k.

Climate suitability

Minimum heating ambient
-22 F[1]
Heating capacity at −22°F
8,700 BTU/h[5]
Certified heating at 5F
16,200 BTU/h[4]
Maximum heating at 5F (manufacturer)
16,200 BTU/h[2]
Rated heating at 17F
9,300 BTU/h[4]
Rated heating at 47F
13,200 BTU/h[4]

Specifications

Show
Manufacturer
Mitsubishi Electric
Brand
Mitsubishi Electric
Product line
M-Series FX Deluxe Hyper-Heat
Model number
MSZ-FX12NL-U1 indoor / MUZ-FX12NLHZ-U1 outdoor
Indoor unit model
MSZ-FX12NL-U1
Outdoor unit model
MUZ-FX12NLHZ-U1
Number of zones
1
Max indoor units
not published
Rated cooling capacity
12,000 BTU/h[4]
Rated heating capacity
13,200 BTU/h[4]
Voltage
208/230V[1]
MCA
14 A[2]
Maximum fuse or breaker size
15 A[2]
Breaker needed
15 A[1]
SEER2
29.9 SEER2[4]
EER2
15.4 EER2[4]
HSPF2 (Region 4)
12.4 HSPF2[4]
HSPF2 (Region 5)
not published
COP
not published
COP at 47F
4.2 COP[2]
COP at 5F
2.2 COP[4]
Minimum outdoor heating temperature
-22 F[1]
Minimum outdoor cooling temperature
not published
Maximum outdoor temperature
115 F[1]
Indoor noise range
cooling 20 , 24 , 29 , 36 , 44; heating 21 , 24 , 29 , 36 , 42[2]
Outdoor noise rating
51 dBA[2]
Indoor weight
31.4 lb[2]
Outdoor weight
89 lb[2]
Refrigerant
R-454B[4]
Refrigerant charge
not published
Manufacturer coverage
not published
Line-set size
1/4 in liquid / 3/8 in suction
Included line-set length
Mitsubishi submittals publish line-size and maximum/precharged piping data; the installer supplies the line set.
Maximum line-set length
65 ft[2]
Max line set per indoor
not published
Maximum elevation difference
40 ft[2]
Max height between indoor units
not published
Wi-Fi support
supported[3]
Energy Star status
ENERGY STAR certified[4]
AHRI certification number
215611126[4]
Warranty
Base: 5 yr parts / 7 yr compressor (licensed HVAC contractor installation); Registered: 10 yr parts / 10 yr compressor (owner-occupied residence registered within 90 days of installation); Program: 12 yr parts / 12 yr compressor (owner-occupied residence installed and registered by a Diamond Contractor within 90 days). Score uses Registered. Additional published terms are shown for reference and not counted in the score.. Standard residential M-Series warranty is 5 years parts and 7 years compressor from installation by a licensed HVAC contractor. Enhanced residential terms are 10 years parts and compressor for an owner-occupied residence registered within 90 days of installation, and 12 years parts and compressor when installed in an owner-occupied residence by a Diamond Contractor and registered by that Diamond Contractor within 90 days.
Install path
Professional install
Retail price
Installed quote only
Available retailers
not published
Manual links
AHRI certificate 215611126, AHRI public detail 215611126, ENERGY STAR exact row for AHRI 215611126, M-Series FX Deluxe Hyper-Heat Mitsubishi Comfort product page, M-Series FX Deluxe Hyper-Heat Mitsubishi Comfort product page, MitsubishiPro product record MUZ-FX12NLHZ-U1, MSZ-FX12NL & MUZ-FX12NLHZ Mitsubishi Electric submittal, METUS Residential M-Series, P-Series and SMART MULTI Limited Warranty Statement
Specification sheet
MSZ-FX12NL & MUZ-FX12NLHZ Mitsubishi Electric submittal
Last sourced date
Jul 23, 2026

Parts and filters

Fits Mitsubishi Electric M-Series FX Deluxe Hyper-Heat 12,000 BTU R-454B 208/230V (MSZ-FX12NL / MUZ-FX12NLHZ). Part numbers and fit notes identify compatibility only; no manufacturer endorsement is implied.

filter-deodorizing

Mitsubishi platinum deodorizing filter

Fits
Mitsubishi Electric M-Series FX Deluxe Hyper-Heat 12,000 BTU R-454B 208/230V (MSZ-FX12NL / MUZ-FX12NLHZ)
OEM part number
MAC-3010FT-E
Filter care
Washable. Vacuum, or soak and rinse in lukewarm water, then shade-dry every 3 months. Replace when dirt or odor cannot be removed by cleaning.
Fit note
Fits MSZ-FX12NL / MUZ-FX12NLHZ. Manufacturer documentation publishes this OEM part number for this model family. No live HVACDirect exact-part offer was found; source through an authorized Mitsubishi Electric dealer with the model and serial number.
Source
Mitsubishi Electric MSZ-FX09NL / MUZ-FX09NLHZ Submittal, INDOOR UNIT ACCESSORIES: MSZ-FX09NL, page p. 4 (Filter Platinum Deodorizing Filter MAC-3010FT-E)

smart-controller-module

Mitsubishi Wireless Interface 2

Fits
Mitsubishi Electric M-Series FX Deluxe Hyper-Heat 12,000 BTU R-454B 208/230V (MSZ-FX12NL / MUZ-FX12NLHZ)
OEM part number
PAC-USWHS002-WF-2
Fit note
Fits MSZ-FX12NL / MUZ-FX12NLHZ. Manufacturer documentation publishes this OEM part number for this model family. HVACDirect was verified as a live exact-part page on 2026-08-01.
Source
Mitsubishi Electric MSZ-FX09NL / MUZ-FX09NLHZ Submittal, INDOOR UNIT ACCESSORIES: MSZ-FX09NL, page p. 4 (Wireless Interface 2 for Comfrot app PAC-USWHS002-WF-2)

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Paid link

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control-interface

Mitsubishi M-Net I/O Control Interface for M-Series

Fits
Mitsubishi Electric M-Series FX Deluxe Hyper-Heat 12,000 BTU R-454B 208/230V (MSZ-FX12NL / MUZ-FX12NLHZ)
OEM part number
MAC-334IF-E
Fit note
Fits MSZ-FX12NL / MUZ-FX12NLHZ. Manufacturer documentation publishes this OEM part number for this model family. HVACDirect was verified as a live exact-part page on 2026-08-01.
Source
Mitsubishi Electric MSZ-FX09NL / MUZ-FX09NLHZ Submittal, INDOOR UNIT ACCESSORIES: MSZ-FX09NL, page p. 4 (M-Net I/O Control Interface for M-Series <sup>2</sup> MAC-334IF-E)

Some retailer links may earn us a commission at no extra cost; paid relationships never change scores or recommendations. Affiliate disclosure

Paid link

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thermostat-interface

Mitsubishi thermostat interface for third-party thermostats

Fits
Mitsubishi Electric M-Series FX Deluxe Hyper-Heat 12,000 BTU R-454B 208/230V (MSZ-FX12NL / MUZ-FX12NLHZ)
OEM part number
PAC-US445CN-1
Fit note
Fits MSZ-FX12NL / MUZ-FX12NLHZ. Manufacturer documentation publishes this OEM part number for this model family. HVACDirect was verified as a live exact-part page on 2026-08-01.
Source
Mitsubishi Electric MSZ-FX09NL / MUZ-FX09NLHZ Submittal, INDOOR UNIT ACCESSORIES: MSZ-FX09NL, page p. 4 (Thermostat Interface for 3rd Party Thermostats PAC-US445CN-1)

Some retailer links may earn us a commission at no extra cost; paid relationships never change scores or recommendations. Affiliate disclosure

Paid link

Check price at HVACDirect

wireless-remote-controller

Mitsubishi RedLINK wireless remote controller

Fits
Mitsubishi Electric M-Series FX Deluxe Hyper-Heat 12,000 BTU R-454B 208/230V (MSZ-FX12NL / MUZ-FX12NLHZ)
OEM part number
MHK2
Fit note
Fits MSZ-FX12NL / MUZ-FX12NLHZ. Manufacturer documentation publishes this OEM part number for this model family. HVACDirect was verified as a live exact-part page on 2026-08-01.
Source
Mitsubishi Electric MSZ-FX09NL / MUZ-FX09NLHZ Submittal, INDOOR UNIT ACCESSORIES: MSZ-FX09NL, page p. 4 (Wireless RedLINK™ Remote Controller MHK2)

Some retailer links may earn us a commission at no extra cost; paid relationships never change scores or recommendations. Affiliate disclosure

Paid link

Check price at HVACDirect
Find this model's filterReplacement Parts & Filters

Electrical requirements

Show
Voltage
not published
Voltage range
208/230V[1]
Phase
1[1]
Frequency
60 Hz[1]
MCA
14 A[2]
Breaker needed
15 A[1]
Maximum breaker size
not published
Maximum fuse size
15 A[2]
Maximum cooling current
not published
Maximum heating current
not published
Manufacturer wire notes
14 AWG indoor-outdoor[2]

Installation considerations

Show
Liquid line
1/4 in[2]
Suction line
3/8 in[2]
Line connection type
not published
Precharged length
25 ft[2]
Included line-set length
Mitsubishi submittals publish line-size and maximum/precharged piping data; the installer supplies the line set.
Maximum line-set length
65 ft[2]
Max line set per indoor
not published
Max height between indoor units
not published
Indoor dimensions
9 x 32 x 9-3/4 in[2]
Outdoor dimensions
31-1/2 x 11-1/4 x 28-1/8 in[2]
Indoor weight
31.4 lb[2]
Outdoor weight
89 lb[2]
Drain size
not published

Comparable models

LG ARTCOOL Deluxe vs Mitsubishi Hyper-Heat (12,000 BTU)

Side-by-side comparison

Related systems and guides

Frequently asked questions

Can I install the Mitsubishi Electric M-Series FX Deluxe Hyper-Heat 12,000 BTU R-454B 208/230V (MSZ-FX12NL / MUZ-FX12NLHZ) myself, or do I need a pro?
Mitsubishi Electric M-Series FX Deluxe Hyper-Heat 12,000 BTU R-454B 208/230V (MSZ-FX12NL / MUZ-FX12NLHZ) 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 Mitsubishi Electric M-Series FX Deluxe Hyper-Heat 12,000 BTU R-454B 208/230V (MSZ-FX12NL / MUZ-FX12NLHZ) keep heating in a cold winter?
The AHRI/ENERGY STAR certification lists 16,200 BTU/h of heating capacity at 5F. Rated heating operation extends down to -22 F. Certified heating efficiency is 12.4 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 Mitsubishi Electric M-Series FX Deluxe Hyper-Heat 12,000 BTU R-454B 208/230V (MSZ-FX12NL / MUZ-FX12NLHZ) need?
Published electrical requirements: 208/230V voltage, 14 A minimum circuit ampacity, and 15 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 65 ft. The outdoor unit's factory charge covers up to 25 ft of line; longer runs need added refrigerant. Measure the planned routing before ordering.
What warranty does the Mitsubishi Electric M-Series FX Deluxe Hyper-Heat 12,000 BTU R-454B 208/230V (MSZ-FX12NL / MUZ-FX12NLHZ) carry?
The manufacturer publishes these warranty tiers: Base: 5 yr parts / 7 yr compressor (licensed HVAC contractor installation); Registered: 10 yr parts / 10 yr compressor (owner-occupied residence registered within 90 days of installation); Program: 12 yr parts / 12 yr compressor (owner-occupied residence installed and registered by a Diamond Contractor within 90 days). Score uses Registered. Additional published terms are shown for reference and not counted in the score.. Registration requirements and proof of qualified installation commonly affect coverage, so read the warranty terms before install day.

Data sources

Show
  1. Mitsubishi Electric Trane HVAC US LLC: MitsubishiPro product record MUZ-FX12NLHZ-U1Sourced - manufacturer product page

    Covers Breaker needed, Frequency, Phase, Voltage range, Minimum outdoor heating temperature, Maximum outdoor temperature and more

  2. Mitsubishi Electric Trane HVAC US LLC: MSZ-FX12NL & MUZ-FX12NLHZ Mitsubishi Electric M-Series FX submittalSourced - manufacturer technical document

    Covers electrical_spec.guaranteed_voltage_range, electrical_spec.indoor_mca_amps, Maximum fuse size, Minimum circuit ampacity, Manufacturer wire notes, Indoor dimensions and more

  3. Mitsubishi Electric Trane HVAC US LLC: M-Series FX Deluxe Hyper-Heat Mitsubishi Comfort product pageSourced - manufacturer product page

    Covers Wi-Fi support

  4. Air-Conditioning, Heating, and Refrigeration Institute: AHRI public detail 215611126 for MSZ-FX12NL / MUZ-FX12NLHZSourced - AHRI directory

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

  5. Northeast Energy Efficiency Partnerships: NEEP ccASHP Product List record 407047Sourced - primary source

    Covers Maximum heating capacity at low temperature, Low-temperature heating capacity test point

  6. Mitsubishi Electric Trane HVAC US LLC: METUS Residential M-Series, P-Series and SMART MULTI Limited Warranty StatementSourced - secondary source

    Covers Additional published compressor warranty, Additional published warranty conditions, Additional published parts warranty, Legacy compressor warranty value, Legacy warranty value, Registered compressor warranty and more

Last updated

Jul 23, 2026