MRCOOL DIY 12K Mini Split System – 5th Generation – 115V

The MRCOOL DIY 12K Mini Split System is a complete 5th Generation single-zone ductless heat pump designed to provide efficient heating and cooling without conventional ductwork. It combines the DIY-12-HP-C-115D25-O outdoor condenser with the DIY-12-HP-WMAH-115D25-O wall-mounted indoor air handler and a 25 ft pre-charged Quick Connect® line set.

With 12,000 BTU of nominal cooling and 12,000 BTU of heating capacity, this 115V system is suitable for appropriately sized residential spaces. Actual coverage depends on climate, insulation, ceiling height, windows, occupancy, construction, and other load factors. Proper system sizing should be confirmed with a load calculation before purchase.

MRCOOL DIY 12K Mini Split System Overview

This single-zone inverter heat pump adjusts compressor operation according to the current heating or cooling demand. Variable-speed operation helps maintain a more consistent indoor temperature and can reduce the repeated full-power cycling associated with traditional fixed-speed equipment.

The matched system is rated at 23.5 SEER2 for cooling efficiency, along with 10.2 HSPF2 for heating efficiency. These ratings apply specifically to the listed matched combination and should not be generalized to other capacities or component pairings.

What’s Included

• Outdoor condenser (115V): MRCOOL DIY-12-HP-C-115D25-O
• Indoor air handler (115V): MRCOOL DIY-12-HP-WMAH-115D25-O
• Refrigerant line: 25 ft pre-charged Quick Connect® line set (1/4″ × 3/8″)
• Controls: Handheld remote and integrated smart-control capability
• Configuration: Single-zone ductless mini split heat pump (115V)

Required electrical components and installation accessories should be reviewed before ordering. Requirements can vary according to the installation location, building configuration, and applicable electrical and mechanical codes.

Key Features

• 115V plug-and-play electrical compatibility
• 12,000 BTU nominal cooling capacity
• 12,000 BTU nominal heating capacity
• 23.5 SEER2 cooling efficiency rating
• 10.2 HSPF2 heating efficiency
• 25 ft pre-charged Quick Connect® line set (1/4″ × 3/8″)
• Variable-speed DC inverter technology
• Single-zone ductless heating and cooling
• R-454B refrigerant platform
• Integrated Wi-Fi and app-based controls
• Follow Me®, Quiet, Auto, Timer, and Dry operating functions
• Gold Fin® condenser coating for corrosion resistance

Technical Specifications

• Brand: MRCOOL
• Series: DIY 5th Generation
• Outdoor model: DIY-12-HP-C-115D25-O
• Indoor model: DIY-12-HP-WMAH-115D25-O
• System type: Single-zone ductless heat pump
• Cooling capacity: 12,000 BTU
• Heating capacity: 12,000 BTU
• Nominal capacity: 1.0 tons
• SEER2: 23.5
• HSPF2: 10.2
• Voltage / Electrical: 115V / 60Hz / 1Ph
• Phase: Single phase (1Ph)
• Frequency: 60 Hz
• Line set size: 1/4″ × 3/8″
• Included line-set length: 25 ft (Pre-charged)
• Refrigerant: R-454B

MRCOOL DIY 12K Mini Split System Compatibility

The MRCOOL DIY 12K Mini Split System must use the listed 12K 115V indoor and outdoor components. Equipment from different capacities, generations, refrigerant platforms, or MRCOOL product lines should not be substituted unless current manufacturer documentation explicitly confirms compatibility.

A professional load calculation is the most reliable way to determine whether a 12,000 BTU system is suitable for a particular application.

Smart Comfort Controls

The MRCOOL DIY 12K Mini Split System includes smart-control capability for compatible Apple and Android mobile devices through the MRCOOL SmartHVAC application. Available functions may include temperature adjustment, operating-mode selection, schedules, fan settings, and remote system control.

Supported Amazon Alexa and Google Assistant integrations can provide compatible voice-control options. The Follow Me® function uses temperature information from the remote-control location to help manage comfort around the occupant instead of relying exclusively on the sensor inside the wall-mounted unit.

R-454B Refrigerant & Line Set Information

The MRCOOL DIY 12K Mini Split System uses R-454B refrigerant and includes a 25 ft Quick Connect® pre-charged line set designed to simplify installation. It must be installed, serviced, and handled according to MRCOOL instructions and all applicable safety requirements for R-454B equipment. R-454B must not be mixed with R-410A or any other refrigerant.

The line set should not be cut or modified. Confirm that the included 25 ft length is appropriate for the planned indoor and outdoor equipment locations before beginning installation.

Warranty and Official Documentation

The MRCOOL DIY 12K Mini Split System comes with a manufacturer’s standard limited warranty providing five years of parts coverage and seven years of compressor coverage from the documented purchase date. Coverage remains subject to MRCOOL’s current terms, exclusions, installation requirements, and claim procedures. Labor, shipping, refrigerant, maintenance, and other costs may not be included.

Review the MRCOOL DIY 5th Generation product brochure, the MRCOOL installation and owner’s manual, and the MRCOOL limited warranty before installing or operating the equipment.

DIY Installation Notice

The DIY design of the MRCOOL DIY 12K Mini Split System and its pre-charged line set simplify several installation steps, but they do not eliminate electrical, structural, drainage, clearance, permitting, or code requirements. The outdoor equipment requires a properly sized 115V dedicated electrical circuit.

Electrical work should be completed or reviewed by a qualified professional when required. Installation must comply with current MRCOOL instructions, the National Electrical Code, applicable building codes, and local permit requirements.

Browse additional ductless mini split systems to compare available capacities and electrical requirements before choosing your system.