How far can the outdoor unit be from the indoor head?

The published maximum line-set length is 100 ft. Measure the planned routing before ordering.

Mitsubishi Electric / M-Series HM

Mitsubishi M-Series HM 24k R-410A 208/230V Mini-Split

Certified capacity: 22,400 BTU/h[3]
SEER2: 20 SEER2[3]
Heating floor: -4 F[4]
Voltage: 208/230V[1]
Install path: Professional install

The M-Series HM 24k is an obsolete (Production Stopped) R-410A value unit at 2 tons: SEER2 20, EER2 8.6, HSPF2 10, with 26,000 BTU of heat at 47F. It has been succeeded by the current R-454B HX 24k.

1 zoneProfessional installLegacy

Need this installed?

Get installation quotes

Error Codes

Mitsubishi Electric M-Series HM 24,000 BTU R-410A 208/230V (MSZ-HM24NA / MUZ-HM24NA)

Image: Mitsubishi Electric

Data completeness: 95%

Last sourced: Jul 23, 2026

SplitAtlas score

7.9 / 10

Methodology

Cooling efficiencyBottom quartile

(20.0 SEER2) among 24k systems

Heating efficiencyAbove average

(10.0 HSPF2) among 24k systems

Cold-weather performanceBottom quartile

(17F certified capacity: 71.2% of the 47F rating; -4 F heating floor) among 24k systems

NoiseAbove average

(32 dBA indoor min / 55 dBA outdoor) among 24k systems

WarrantyTop quartile

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

Feature setBottom quartile

(1 verified feature) 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

22,400BTU/h[3]

Rated heating

26,000BTU/h[3]

Buyer review snapshot

Best for / skip if

Skip if

You are shopping for a current-generation recommendation; catalog lifecycle is LEGACY.

Install difficulty

Professional install

Electrical: 208/230V; MCA 14 A; breaker/fuse 15 A.
Line set: connection type not sourced; max 100 ft.

Alternatives

Blueridge XS3 High Efficiency 24,000 BTU R-454B 208/230V (BXAFA24WM0 / BXS3A24SC0)
8.9 score / 24k / SEER2 23 / -13 F heating floor / 230V
Exact destination at Alpine Home Air: $1,939.00, checked Jul 24, 2026
ACiQ Extreme 24,000 BTU R-454B 208/230V (ACIQ-24W-HH-MD / ACIQ-24ZPL-HP230C)
8.8 score / 24k / SEER2 21 / -22 F heating floor / 230V
Exact destination at HVACDirect: $2,399.99, checked Jul 26, 2026
Senville ELITE 24,000 BTU R-454B 208/230V (SENE-24EL-IHH / SENE-24EL-OH)
8.7 score / 24k / SEER2 25 / -22 F heating floor / 187-253V
Exact destination at Senville: $2,099.99, checked Jul 24, 2026

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: 5
Newest source retrieved: Jul 23, 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

Strengths

26,000 BTU rated heat at 47F - strong capacity for a value 2-ton unit.
SEER2 20 / HSPF2 10 with Mitsubishi dealer support and reliability.

Weaknesses

Production Stopped/obsolete and R-410A - phase-out refrigerant.
EER2 8.6 - low full-load cooling efficiency; no published 5F rating.
The current HX 24k (R-454B) is the recommended replacement.

Climate suitability

Minimum heating ambient: -4 F[4]
Certified heating at 5F: not published
Rated heating at 17F: 18,500 BTU/h[3]
Rated heating at 47F: 26,000 BTU/h[3]

Specifications

Show

Manufacturer: Mitsubishi Electric
Brand: Mitsubishi Electric
Product line: M-Series HM
Model number: MSZ-HM24NA-U1 indoor / MUZ-HM24NA-U1 outdoor
Indoor unit model: MSZ-HM24NA-U1
Outdoor unit model: MUZ-HM24NA-U1
Number of zones: 1
Max indoor units: not published
Rated cooling capacity: 22,400 BTU/h[3]
Rated heating capacity: 26,000 BTU/h[3]
Voltage: 208/230V[1]
MCA: 14 A[2]
Maximum fuse or breaker size: 15 A[2]
Breaker needed: not published
SEER2: 20 SEER2[3]
EER2: 8.6 EER2[3]
HSPF2 (Region 4): 10 HSPF2[3]
HSPF2 (Region 5): not published
COP: not published
COP at 47F: 3.05 COP[2]
COP at 5F: not published
Minimum outdoor heating temperature: -4 F[4]
Minimum outdoor cooling temperature: 14 F[4]
Maximum outdoor temperature: 115 F[4]
Indoor noise range: cooling 50-44-38-33; heating 50-44-38-32[2]
Outdoor noise rating: 55 dBA[2]
Indoor weight: not published
Outdoor weight: 121 lb[2]
Refrigerant: R-410A[3]
Refrigerant charge: not published
Manufacturer coverage: not published
Line-set size: 3/8 in liquid / 5/8 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: 100 ft[2]
Max line set per indoor: not published
Maximum elevation difference: 50 ft[2]
Max height between indoor units: not published
Wi-Fi support: supported[2]
Energy Star status: Not ENERGY STAR certified[3]
AHRI certification number: 209832269[3]
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 209832269, AHRI public detail 209832269, ENERGY STAR exact row for AHRI 209832269, M-Series HM Mitsubishi Comfort product page, M-Series HM Mitsubishi Comfort product page, MitsubishiPro product record MUZ-HM24NA-U1, MSZ-HM24NA & MUZ-HM24NA Mitsubishi Electric submittal, METUS Residential M-Series, P-Series and SMART MULTI Limited Warranty Statement
Specification sheet: MSZ-HM24NA & MUZ-HM24NA Mitsubishi Electric submittal
Last sourced date: Jul 23, 2026

Parts and filters

Fits Mitsubishi Electric M-Series HM 24,000 BTU R-410A 208/230V (MSZ-HM24NA / MUZ-HM24NA). Part numbers and fit notes identify compatibility only; no manufacturer endorsement is implied.

filter-anti-allergy