Mitsubishi 12,000 BTU WX-Series 18 SEER2 Single Zone Wall Mount Mini Split Heat Pump System - R454B | 230V

Mitsubishi WX-Series 12K BTU Single-Zone Ductless Mini Split Heat Pump

Value-focused Mitsubishi comfort for one dedicated space. This WX-Series ductless mini split pairs the MUZ-WX12NL outdoor heat pump with the MSZ-WX12NL wall-mounted indoor unit for efficient heating and cooling without adding ductwork.

With 12,000 BTU of rated cooling, 12,200 BTU of rated heating, and 18.0 SEER2 efficiency, this system is a strong fit for bedrooms, offices, guest rooms, additions, and other small-to-medium spaces where a dedicated comfort zone makes more sense than extending central ductwork.

Not sure if 12K is the right size? Confirm your room load, insulation, sun exposure, and installation plan before ordering so the system is matched correctly to the space.

Currently only available in GA, TN, OH, IN, and KY

At a Glance:

Best For	One-zone heating and cooling with a wall-mounted indoor unit
System Models	MUZ-WX12NL outdoor unit + MSZ-WX12NL indoor unit
Capacity	12,000 BTU cooling / 12,200 BTU heating
Efficiency	18.0 SEER2 / 9.0 EER2 / 8.5 HSPF2
Voltage	208/230V, 1 phase
Refrigerant	R-454B
Installation Type	Professional HVAC installation recommended

Why Choose This Mitsubishi WX System?

• Entry-level Mitsubishi option: A practical choice for homeowners who want Mitsubishi single-zone comfort with a simpler 18 SEER2 equipment tier.
• Dedicated room comfort: Heat and cool one room or area without tying that space to a central duct system.
• Efficient inverter performance: Mitsubishi inverter technology adjusts output as conditions change, helping maintain steadier comfort than basic on/off systems.
• Year-round heat pump operation: Provides both air conditioning and heating from the same system.
• Quiet wall-mounted design: The indoor unit mounts high on the wall to distribute air through the room while keeping floor space open.
• Modern R-454B refrigerant: Built for Mitsubishi's current R-454B equipment generation.
• Warranty confidence: Mitsubishi lists a 10-year parts and compressor limited warranty when eligible equipment is registered within 90 days, subject to warranty terms.

What Is Included?

• 1 Mitsubishi MUZ-WX12NL outdoor heat pump condenser
• 1 Mitsubishi MSZ-WX12NL wall-mounted indoor air handler
• Wireless remote control capability for the indoor unit

Before You Order:

• Have your installer confirm the room load and that a 12K system is appropriate for the space.
• Confirm line-set length, indoor and outdoor placement, condensate routing, electrical requirements, and local code requirements before purchase.
• This is not a DIY quick-connect system. Refrigerant piping, evacuation, electrical work, startup, and commissioning should be handled by a qualified HVAC professional.
• Line sets, wall brackets, disconnects, pads, electrical materials, and installation accessories may be sold separately unless specifically included.

Frequently Asked Questions:

What makes this different from the HX-Series?
The WX-Series is Mitsubishi's entry-level single-zone heat pump tier in this catalog, with 18.0 SEER2 ratings across these capacities. HX steps up to 20.0 SEER2.

Does this system heat and cool?
Yes. This is a heat pump system designed for both air conditioning and heating.

Is this a DIY system?
No. This Mitsubishi system should be installed by a qualified HVAC professional.

Does it use R-454B refrigerant?
Yes. The MUZ-WX12NL / MSZ-WX12NL system is part of Mitsubishi's R-454B equipment lineup.

Specifications:

BRAND NAME	Mitsubishi
SERIES	WX-Series
SYSTEM TYPE	Ductless mini split heat pump
OUTDOOR MODEL	MUZ-WX12NL
INDOOR MODEL	MSZ-WX12NL
ZONE CAPACITY	1 zone
COOLING CAPACITY	12,000 BTU
HEATING CAPACITY	12,200 BTU
AHRI CERTIFICATE NUMBER	216626282
SEER2	18.0
EER2	9.0
HSPF2	8.5
REFRIGERANT TYPE	R-454B
POWER SUPPLY	208/230V, 1 phase
MAX OVERCURRENT PROTECTION	17 A
LINE SET SIZE	1/4 in liquid / 3/8 in gas
OUTDOOR DIMENSIONS	31 in W x 22 in H x 11 in D
INDOOR DIMENSIONS	33 in W x 11 in H x 9 in D
REGISTERED WARRANTY	10-year parts and compressor limited warranty when registered within 90 days; terms apply
NON-REGISTERED WARRANTY	5-year parts / 7-year compressor limited warranty; terms apply