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MUFZ-KJ18NAHZ

MUFZ-KJ18NAHZ is in the certified data.

Its certified ratings are 10.3 HSPF2 and 22.0 SEER2.

Mitsubishi Electric · mini-split heat pump

MUFZ-KJ18NAHZ is in the certified data as of Sep 19, 2026.

Heating at 47°F

21,000

12,800 at 17°F

NR at 5°F

Btu/h, certified

NR COP at 5°F

Cooling at 95°F

17,000

Btu/h, certified

EER2 12.6 at 95°F

SEER2 22.0

Heating and cooling by outdoor temperature

Certified heating at 5, 17, and 47°F and cooling at 95°F for MUFZ-KJ18NAHZ, by outdoor temperature Heating: no certified figure at 5°F, 12,800 Btu/h at 17°F, 21,000 Btu/h at 47°F. Cooling: 17,000 Btu/h at 95°F. The bars start at zero. Median of 1.5-ton mini-split models: 14,200 Btu/h at 5°F, 14,800 Btu/h at 17°F, 18,000 Btu/h at 47°F, 18,000 Btu/h at 95°F. 0 5,000 10,000 15,000 20,000 25,000 Btu/h NR 5°F 12,800 17°F 21,000 47°F 17,000 95°F Outdoor temperature (°F)
  • Heating output
  • Cooling output
  • Median of 1.5-ton mini-split models
  • Example heating load
  • Example cooling load
  • Frosting range, 17 to 45°F

This pairing delivers 21,000 Btu/h of heat at 47°F and 12,800 Btu/h at 17°F. It delivers 17,000 Btu/h of cooling at 95°F. At 95°F that is 10,000 Btu/h above the example cooling load of 7,000 Btu/h.

Each bar is a separate certified test, drawn at its outdoor temperature, starting at zero. The 47°F figure is at normal speed; the 17 and 5°F figures are at full speed. The short dark line on each bar is the median of 1.5-ton mini-split models, one value per model. The shaded 17 to 45°F band is the frosting range: the outdoor coil can frost, and the unit pauses to defrost.

The dashed lines are example loads for a typical area of about 600 sq ft where winters reach 5°F: heating runs from 14,000 Btu/h at 5°F to 0 at 65°F, and cooling runs from 0 at 65°F to 7,000 Btu/h at 95°F, at 1,000 sq ft per ton. A house in a hot climate or with large west-facing windows can need twice as much cooling. They are examples, not your building.

Calculate heating and cooling for your house

AHRI certificate 204629180 · listed by Mitsubishi Electric · certified Jan 16, 2024 · 3 pairings on 3 certificates share these values

All rebate programs and their published thresholds

Certified output and power use

Certified output for the selected pairingThe four bars share one scale. The comparison is with the median of 1.5-ton mini-split models. Heating tests run at 70°F indoors. The cooling test runs at 80°F indoors.
Outdoor temperature Certified outputBtu/h One scale vs class median COPat 5°F
5°Ffull speed NR NR NR
17°Ffull speed 12,8003.75 kW −14% NR
47°Fnormal speed 21,0006.15 kW +17% NR
95°Fcooling, full load 17,0004.98 kW — NR

EER2 12.6 in that test. SEER2 22.0 over the modeled cooling season.

Power use at each temperature

Electrical input in the 5°F full-speed test
NRkW
Electrical input in the 95°F cooling test
1.35kW
Seasonal average heating COP
3.02

These exclude backup resistance heat.

Updated Sep 19, 2026 · Methodology

How it compares with other 18,000 Btu heat pumps

1.5-ton mini-split models

This pairing at 5°F
NR
This unit at 5°F median across its pairings
NR
Median of 1.5-ton mini-split models at 5°F
14,200 Btu/h
Models in this group
1,110

This size class is defined by cooling capacity, so cooling is not compared here.

Every 18,000 Btu (1.5-ton) unit, ranked by cooling efficiency, then heating efficiency

Certified values for MUFZ-KJ18NAHZ

3 pairings · 3 AHRI certificates

This pairing is the one shown above. Under all pairings, a single figure means every pairing agrees and a range means the pairing decides.

This pairingAll pairings
Heating
Heat output at 47°F normal speed 21,000 Btu/h 21,000 Btu/h
Heat output at 17°F full speed 12,800 Btu/h 12,800 Btu/h
Heat output at 5°F full speed NR NR
Heat output below 5°F NR NR
Cold output 5°F output as a % of the 47°F rating NR NR
COP at 5°F full speed NR —
HSPF2 Region IV 10.3 10.3
Cooling
Cooling capacity at 95°F full-load test 17,000 Btu/h 17,000 Btu/h
EER2 at 95°F 12.6 12.6
SEER2 cooling season 22.0 22.0
Cooling at other temperatures NR NR
Equipment and listing
Refrigerant R-410A
Compressor Variable speed
Indoor unit NTXFKS18A112A* 3 indoor units
FurnaceNo furnace None
Cold-climate designation EPA's designation, as published NC NC
ENERGY STAR Most Efficient EPA's designation, as published No On no pairings
Where it is sold United States US and Canada
Model string as certified MUFZ-KJ18NAHZ***

Pairings, by indoor-unit class

3 indoor units · 3 certified pairings

One row per indoor unit certified with this outdoor unit.

Ductless indoor · 3 indoor units

  1. MFZ-KJ18NA*** Mitsubishi Electric NRat 5°F, full speed

    1 pairing · 47°F 21,000 Btu/h · 95°F cooling 17,000 Btu/h · Cold output NR · COP —

  2. NAXFKS18A112A* Mitsubishi Electric NRat 5°F, full speed

    1 pairing · 47°F 21,000 Btu/h · 95°F cooling 17,000 Btu/h · Cold output NR · COP —

  3. NTXFKS18A112A* Mitsubishi Electric NRat 5°F, full speed

    1 pairing · 47°F 21,000 Btu/h · 95°F cooling 17,000 Btu/h · Cold output NR · COP —

Indoor units in the ductless indoor class
Indoor unit Brand At 5°FBtu/h · full speed At 47°FBtu/h · normal speed At 95°FBtu/h · cooling Cold output% of 47°F rating COP 5°Ffull speed Cold climate Pairings
MFZ-KJ18NA*** Mitsubishi Electric NR 21,000 17,000 NR — NC 1
NAXFKS18A112A* Mitsubishi Electric NR 21,000 17,000 NR — NC 1
NTXFKS18A112A* Mitsubishi Electric NR 21,000 17,000 NR — NC 1

The share is heat output at 5°F divided by the 47°F rating. Tests use different compressor speeds.

Showing 3 of 3 indoor units

Sold as, and units with identical certified values

Brands listing this model number

Model number as listed

  • MUFZ-KJ18NAHZ*** 3 pairings

What affects the price

We don't have prices. These things drive the cost.

  • The size of the unit, and the indoor equipment on the same certificate.
  • Whether existing ductwork is reused, altered, or replaced.
  • The electrical work: a circuit, a disconnect, and sometimes a panel change.
  • Refrigerant line length and how the outdoor unit is mounted.
  • Permits and inspection, which vary by municipality.
  • Removing and disposing of the old equipment.
  • Local labor rates and how busy the season is.
  • Rebates and tax credits, which change and have deadlines.

History and definitions

History

First certified record
Most recent certified record
Measurements reported
Jan 16, 2024
Status
In the certified data

Field definitions

COP
Heat delivered for each unit of electricity used. A COP of 2.5 gives 2.5 times the heat of an electric baseboard heater.
HSPF2
Heating efficiency over a typical season. Higher uses less electricity.
SEER2
Cooling efficiency over a typical season. Higher uses less electricity.
EER2
Cooling output divided by electrical input in the 95°F full-load test, in Btu/h per watt.
Cold output
Heat output at 5°F as a percentage of the 47°F rating.
% of rating at 17°F
Heat output at 17°F as a percentage of the 47°F rating.

NR not in the certified dataNC not cold-climate certifiedSP single pairing onlyVP varies by pairing; see the pairings tableWD withdrawn since the certified data was last read

Cite or print this page

Heat Pump List, “MUFZ-KJ18NAHZ — certified heat output”. Certified figures dated , checked daily.
https://heatpumplist.com/model/mufz-kj18nahz