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MXZ-SM42NLHZ

MXZ-SM42NLHZ is in the certified data.

Its certified full-speed heating output at 5°F is 48,000 Btu/h, 100% of its 47°F rating (tests at different compressor speeds) across its certified pairings.

Mitsubishi Electric · mini-split heat pump

MXZ-SM42NLHZ is in the certified data as of Sep 19, 2026.

6 certified pairings with 5 different figures. See all

Heating at 47°F

48,000

34,000 at 17°F

48,000 at 5°F

Btu/h, certified

2.00 COP at 5°F

Cooling at 95°F

42,000

Btu/h, certified

EER2 13.4 at 95°F

SEER2 21.5

Heating and cooling by outdoor temperature

Certified heating at 5, 17, and 47°F and cooling at 95°F for MXZ-SM42NLHZ, by outdoor temperature Heating: 48,000 Btu/h at 5°F, 34,000 Btu/h at 17°F, 48,000 Btu/h at 47°F. Cooling: 42,000 Btu/h at 95°F. The bars start at zero. Median of 3.5-ton mini-split models: 36,000 Btu/h at 5°F, 32,000 Btu/h at 17°F, 44,000 Btu/h at 47°F, 42,000 Btu/h at 95°F. 0 10,000 20,000 30,000 40,000 50,000 Btu/h 48,000 5°F 34,000 17°F 48,000 47°F 42,000 95°F Outdoor temperature (°F)
  • Heating output
  • Cooling output
  • Median of 3.5-ton mini-split models
  • Example heating load
  • Example cooling load
  • Frosting range, 17 to 45°F

This pairing delivers 48,000 Btu/h of heat at 47°F, 34,000 Btu/h at 17°F, and 48,000 Btu/h at 5°F, 100% of its 47°F rating. It delivers 42,000 Btu/h of cooling at 95°F. At 5°F that is 12,000 Btu/h above the example heating load of 36,000 Btu/h; at 95°F it is 24,000 Btu/h above the example cooling load of 18,000 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 3.5-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 1,500 sq ft where winters reach 5°F: heating runs from 36,000 Btu/h at 5°F to 0 at 65°F, and cooling runs from 0 at 65°F to 18,000 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 215685465 · listed by Mitsubishi Electric · certified Sep 2, 2025 · 2 pairings 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 3.5-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 48,00014.07 kW +33% 2.00
17°Ffull speed 34,0009.96 kW +6% NR
47°Fnormal speed 48,00014.07 kW +9% NR
95°Fcooling, full load 42,00012.31 kW — NR

EER2 13.4 in that test. SEER2 21.5 over the modeled cooling season.

Power use at each temperature

Electrical input in the 5°F full-speed test
7.03kW
Electrical input in the 95°F cooling test
3.13kW
Seasonal average heating COP
3.25

These exclude backup resistance heat.

Updated Sep 19, 2026 · Methodology

How it compares with other 42,000 Btu heat pumps

3.5-ton mini-split models

This pairing at 5°F
48,000 Btu/h
This unit at 5°F median across its pairings
48,000 Btu/h
Median of 3.5-ton mini-split models at 5°F
36,000 Btu/h
Models in this group
161

This unit is above 93% of them, at number 11 of 161 by heat at 5°F. The middle half of the group runs 33,000 to 37,000 Btu/h.

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

Closest models by heat at 5°F

Every 42,000 Btu (3.5-ton) unit, ranked by cooling efficiency, then heating efficiency

Certified values for MXZ-SM42NLHZ

6 pairings · 6 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 48,000 Btu/h 48,000 Btu/h
Heat output at 17°F full speed 34,000 Btu/h 32,000–34,000 Btu/h
Heat output at 5°F full speed 48,000 Btu/h 48,000 Btu/h
Heat output below 5°F NR NR
Cold output 5°F output as a % of the 47°F rating 100%
COP at 5°F full speed 2.00 1.86–2.00
HSPF2 Region IV 11.1 10.0–11.1
Cooling
Cooling capacity at 95°F full-load test 42,000 Btu/h 42,000 Btu/h
EER2 at 95°F 13.4 10.4–13.4
SEER2 cooling season 21.5 17.0–21.5
Cooling at other temperatures NR NR
Equipment and listing
Refrigerant R-454B
Compressor Variable speed
Indoor unit None listed None
FurnaceNo furnace None
Cold-climate designation EPA's designation, as published Yes On every pairing
ENERGY STAR Most Efficient EPA's designation, as published Yes On every pairing
Where it is sold United States United States
Model string as certified MXZ-SM42NLHZ***

Pairings, by indoor-unit class

6 certified pairings

One row per indoor unit certified with this outdoor unit.

Ductless indoor

  1. None listed Mitsubishi Electric 48,000 Btu/hat 5°F, full speed

    6 pairings · 47°F 48,000 Btu/h · 95°F cooling 42,000 Btu/h · Cold output 100% · COP 1.93

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
None listed Mitsubishi Electric 48,000 48,000 42,000 100% 1.93 Yes 6

The share is heat output at 5°F divided by the 47°F rating.

Sold as, and units with identical certified values

Brands listing this model number

Model number as listed

  • MXZ-SM42NLHZ*** 3 pairings
  • MXZ-SM42NLHZ-** 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.

Product history

  • MXZ-SM42NLHZ first appeared in the certified data between November 2024 and February 2025.

History and definitions

History

First certified record
Most recent certified record
Measurements reported
Sep 2, 2025
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, “MXZ-SM42NLHZ — certified heat output”. Certified figures dated , checked daily.
https://heatpumplist.com/model/mxz-sm42nlhz