DIY 5th Gen Mini Split – 12K BTU

Fast, DIY heating & cooling for a single room

  • DIY Installation
  • Single-Zone Mini-Split System
  • 115V
  • Up to 20+ SEER2
  • Ideal Coverage ~400-550 sq ft

Model: DIYSZ-SYS-12

The MRCOOL DIY 5th Gen 12K BTU 115V Mini Split Heat Pump System delivers true do-it-yourself heating and cooling with no special HVAC tools required. Designed for spaces around 550 sq ft, it includes a pre-charged 25 ft QuickConnect® line set, DIYPro® cable, WiFi control, inverter-driven efficiency, and Energy Star certified performance.
$2,359 Complete System Price
  • In stock — ships in 1-2 business days
  • Financing options available at checkout

As low as $197/mo with Affirm

  • Easy DIY installation
  • Heats & cools one room
  • Inverter heat pump tech
  • Smart WiFi app control
  • Ultra-quiet operation

Quick Answers Before You Buy

Is this a DIY system?
Yes. This system is designed for easy DIY homeowner installation — no special tools required.
Does this system provide heating and cooling?
Yes — inverter heat pump technology provides efficient heating and cooling year-round.
Not sure which size you need?
Sq ft and home characteristics determine sizing. Use our Find My System tool for guidance.
✓ Secure checkout ✓ Fast, free nationwide delivery ✓ Expert support ✓ Factory warranty ✓ Financing options

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Comfort Made Simple. Install It Yourself.

Key Features

Whole-home heating & cooling

Whole-home heating & cooling

Delivers consistent, balanced cooling to every room through your home’s duct system.

High-efficiency performance

High-efficiency performance

Modern energy-efficient operation helps reduce cooling costs while maintaining reliable comfort.

Works with your existing ductwork

Works with your existing ductwork

Easily integrate with most existing ducted HVAC systems and home layouts.

Will This System Work For Your Space?

BEST FOR Rooms
400-550 sq ft
ELECTRICAL 115V
circuit required
INSTALLATION DIY QuickConnect™
system
CLIMATE Heating down to −13°F

Still unsure? Find My System

Learn More About This System

Detailed Specifications & Documentation

True DIY Comfort for Bedrooms, Offices, Garages, and Medium-Sized Living Spaces

The MRCOOL DIY 5th Gen 12K BTU 115V Single Zone Mini Split System
is designed specifically for homeowners who want efficient ductless heating
and cooling without requiring specialized HVAC tools or traditional
professional installation.

Ideal for bedrooms, larger home offices, garages, workshops, enclosed
sunrooms, and many spaces around 550 square feet, this system combines
modern inverter efficiency, quiet performance, smart control convenience,
and one of the easiest installation processes available in a ductless system.

Quick System Snapshot
  • 12,000 BTU cooling capacity
  • 12,000 BTU heating capacity
  • 23.5 SEER2 efficiency rating
  • 10.2 HSPF2-4 heating efficiency
  • 115V power requirement
  • Designed for spaces around 550 sq ft
  • 25 ft pre-charged QuickConnect® line set included
  • DIYPro® armored cable included
  • Energy Star® certified
  • WiFi smartphone control included
  • R-454B refrigerant
Designed for Real DIY Installation

Unlike traditional mini split systems that require vacuum pumps,
gauges, refrigerant charging, and specialized HVAC tools, the DIY 5th Gen
uses a factory pre-charged QuickConnect® line set that simplifies installation
for capable homeowners.

The included DIYPro® armored cable further streamlines installation while
helping protect the communication wiring without requiring separate conduit
in many applications.

Efficient Inverter-Driven Performance

The variable-speed inverter compressor continuously adjusts output based on
room conditions instead of repeatedly cycling on and off like older fixed-speed
systems.

This helps maintain more consistent indoor temperatures while improving
overall efficiency, reducing energy consumption, and delivering quieter
everyday comfort throughout changing conditions.

Smart Comfort and Everyday Convenience

The included Smart HVAC Controller® provides WiFi app control from your
smartphone or tablet, while built-in compatibility with Amazon Alexa and
Google Assistant adds convenient voice control integration.

  • WiFi smartphone control included
  • Amazon Alexa & Google Assistant compatible
  • Follow Me® temperature sensing remote
  • Auto restart after power outages
  • Louver position memory
  • Washable air filters
Built for Long-Term Reliability

The outdoor condenser features Gold Fin® corrosion-resistant protection
designed to help withstand long-term environmental exposure, including
humid and coastal conditions.

The system also uses modern R-454B refrigerant and includes low ambient
cooling capability for added flexibility throughout the year.

Important Information
  • Single-zone wall-mounted mini split system
  • 25 ft QuickConnect® line set included
  • Maximum breaker size: 20A
  • Minimum circuit ampacity: 18A
  • Professional electrical work may still be required depending on local code
  • Coverage varies based on insulation, climate, windows, and ceiling height

“`

  • Air Handler TypeWall Mount
  • Capacity12000 BTU
  • Coverage400-550 sq ft
  • Installation TypeDIY
  • System TypeSingle Zone Mini Split
  • Voltage115V
  • SeriesDIY 5th Gen Single Zone
  • Line Set TypeQuickConnect (DIY)
  • Zone TypeSingle Zone
  • Cold Climate EligibleFalse
  • SEER2 Rating20+ SEER2

Installation guides, spec sheets, and certifications will be available for download soon.

Will this work for my space?
Yes — 5th Gen DIY Single Zone systems heat and cool individual rooms or open spaces. Choose system size based on room square footage and layout for best comfort. If unsure, our sizing guide or support team can help.
Can I install this?
Yes — 5th Gen systems use pre-charged Quick Connect® line sets so homeowners can install without vacuum pumps, gauges, or refrigerant handling. No HVAC license needed.
Does it heat in winter?
Yes — 5th Gen systems provide strong, reliable heating even in low outdoor temperatures, making them ideal for garages, basements, bonus rooms, and colder climates.
How loud is it?
Very quiet. Both indoor and outdoor units are designed for low noise levels and smooth operation, even at night.
What else do I need?
Everything needed for installation is included: indoor air handler, outdoor condenser, pre-charged Quick Connect® line set, communication wire, wall sleeve, drain hose, remote control, and mounting hardware. Only basic mounting tools are required.
What is the warranty for 5th Gen DIY systems?
Warranty includes a 5-year parts warranty and 7-year compressor warranty. Warranty remains valid with homeowner installation.
How long does installation take?
Most homeowners complete installation in 4–8 hours, depending on room layout and mounting conditions.

Need Help From a MRCOOL Expert?

Not sure which system is right? Our HVAC specialists can help you choose the correct size and configuration.

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