MRCOOL DIY® Select 12K BTU Single Zone Mini Split Heat Pump 115V
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Powerful DIY Comfort for Medium-Sized Spaces
The MRCOOL DIY® Select 12,000 BTU Single Zone Mini Split Heat Pump delivers reliable year-round heating and cooling for spaces up to 550 square feet without the cost of professional installation. Designed for true DIY installation, this 115V mini split system includes an 11.5 ft pre-charged Quick Connect® line set, allowing homeowners to install their own HVAC system without vacuum pumps, gauges, or refrigerant handling.
Built on proven MRCOOL® technology, the DIY Select series offers a budget-friendly alternative to traditional ductless systems while still delivering the features that matter: inverter-driven efficiency, quiet operation, smart control, and simplified installation.
What Makes the DIY Select 12K Different?
Many low-cost mini split systems still require proper evacuation, specialized tools, and refrigerant handling. When those steps are skipped, performance and longevity can suffer. The MRCOOL DIY Select 12K eliminates that risk with factory pre-charged Quick Connect® fittings, allowing homeowners to install the system without opening the refrigerant circuit.
The result is a simpler, cleaner, and more reliable installation process that removes one of the biggest barriers to owning a ductless mini split system.
Key Features
- 12,000 BTU heating and cooling for spaces up to 550 sq. ft.
- 115V operation ideal for residential applications
- Includes 11.5 ft pre-charged Quick Connect® line set
- No vacuuming or refrigerant handling required
- Up to 17.5 SEER2 cooling efficiency
- Up to 9.0 HSPF2-4 heating efficiency
- Inverter-driven compressor for consistent temperature control
- Ultra-quiet operation as low as 17.5 dB(A)
- Smart control via MRCOOL® Comfort App
- Compatible with Alexa and Google Assistant
- R-454B refrigerant for future-ready performance
- White indoor air handler standard
- Black indoor air handler option coming soon
Includes 11.5 ft Pre-Charged Line Set
The included 11.5 ft pre-charged line set is a major advantage over standard DIY systems that often include longer 16 ft or 25 ft line sets. This shorter length helps reduce excess coiling, resulting in a cleaner and more professional installation.
For installations requiring longer runs, optional pre-charged line sets are available in 16 ft, 25 ft, 35 ft, and 50 ft lengths.
Designed for True DIY Installation
The MRCOOL DIY Select 12K removes the most complicated part of mini split installation. The pre-charged Quick Connect® line set eliminates the need for vacuum pumps, gauges, and refrigerant handling, allowing homeowners to install the system with basic tools.
This significantly reduces installation cost while maintaining reliable system performance, making it an ideal solution for homeowners who want professional-level comfort without the professional install bill.
White Standard, Black Option Coming Soon
The system includes a standard white indoor air handler designed to blend into most residential spaces. MRCOOL has also introduced a black air handler option for the DIY Select series, ideal for modern interiors, garages, and design-focused environments.
The black SKU has not yet been released but will be available as a selectable option once launched.
Smart Control and Connected Comfort
Control your system from anywhere using the MRCOOL® Comfort App. Adjust temperature, set schedules, and monitor performance directly from your smartphone. Voice control compatibility with Amazon Alexa and Google Assistant adds even more convenience.
12,000 BTU System
| System Type | Single Zone Mini Split Heat Pump |
|---|---|
| Cooling Capacity | 12,000 BTU |
| Heating Capacity | 12,000 BTU |
| Voltage | 115V |
| Coverage Area | Up to 550 sq. ft. |
| SEER2 | 17.5 |
| HSPF2-4 | 9.0 |
| Refrigerant | R-454B |
| Included Line Set | 11.5 ft pre-charged Quick Connect® line set |
| Optional Line Set Lengths | 16 ft, 25 ft, 35 ft, and 50 ft |
| Indoor Noise Level | As low as 17.5 dB(A) |
| System SKU | DIYS-12-HP-115A11-O |
Ideal Applications
- Bedrooms
- Living rooms
- Home offices
- Garages and workshops
- Rental properties
- Additions and bonus rooms
Why Buy from MRCOOL DIY Direct?
MRCOOL DIY Direct specializes in MRCOOL DIY mini split systems, installation accessories, and replacement parts. We help homeowners across the country choose the right system for their space, layout, and budget.
If you're looking for a mid-size DIY mini split that balances power, efficiency, and ease of installation, the MRCOOL DIY Select 12,000 BTU Mini Split Heat Pump delivers dependable comfort without the installation cost.
DIY Single-Zone System
Outdoor Condenser
Indoor Air Handler
Pre-Charged DIY Line Set
Control Wire
Wireless Remote
Installation Manual
WiFi Dongle / Smart Controller Adapter
Wall Mounting Plate
Wall Sleeve / Wall Pass-Through
Line Set Wrap / Insulation Tape
Download installation manuals, spec sheets, and warranty documents for this system.
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Rated 4.7 / 5 Stars
4700+ Verified Reviews
Comfort That Speaks for Itself
See why homeowners and pros alike trust MRCOOL DIY systems to deliver comfort, savings, and easy installation.
I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!
Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency
Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.
I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.
Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.
Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!
I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.
I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!
Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency
Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.
I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.
Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.
Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!
I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.
I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!
Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency
Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.
I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.
Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.
Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!
I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.
I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!
Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency
Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.
I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.
Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.
Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!
I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.
I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!
Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency
Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.
I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.
Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.
Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!
I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.
I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!
Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency
Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.
I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.
Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.
Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!
I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.
I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!
Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency
Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.
I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.
Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.
Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!
I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.
I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!
Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency
Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.
I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.
Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.
Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!
I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.
I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!
Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency
Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.
I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.
Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.
Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!
I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.
I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!
Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency
Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.
I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.
Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.
Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!
I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.
MRCOOL DIY® Select Mini Split Heat Pump FAQs
Find answers to common questions about the MRCOOL DIY® Select single-zone mini split system, including DIY installation, included Quick Connect® line sets, heating and cooling performance, voltage requirements, and energy efficiency.
Why is the MRCOOL DIY® Select more affordable than the Easy Pro™ or DIY® 5th Gen series?
The MRCOOL DIY® Select series was designed as a value-focused DIY ductless heat pump system that delivers reliable cooling and heating performance at a more budget-friendly price point.
Unlike premium low-ambient or enhanced cold-climate systems, the DIY® Select uses a more standard heat pump design focused on efficient everyday comfort in typical residential applications.
The system still provides excellent cooling performance and dependable heating in colder temperatures, including operation down to around 0°F outdoor temperatures. However, like most standard heat pump systems, heating efficiency and capacity will gradually decrease as outdoor temperatures become extremely cold.
This allows the DIY® Select series to offer a lower purchase price while still providing the convenience of DIY installation, inverter technology, and year-round heating and cooling.
The result is an affordable ductless solution designed to compete with entry-level imported mini split systems while still delivering the quality, support, and reliability customers expect from MRCOOL.
Can I install the MRCOOL DIY® Select system myself?
Yes. The MRCOOL DIY® Select system is designed specifically for homeowner installation using the included pre-charged Quick Connect® line set. Unlike traditional mini split systems, this system does not require special HVAC tools, vacuum pumps, or professional refrigerant charging during standard installation.
The system includes detailed installation instructions and is ideal for DIY homeowners looking to add efficient heating and cooling without hiring an HVAC contractor.
Does the MRCOOL DIY® Select include the line set?
Yes. Each MRCOOL DIY® Select single-zone system includes a pre-charged Quick Connect® line set designed for fast and simple installation.
The included line set length varies by model configuration. The pre-charged design helps eliminate the need for vacuuming or charging the refrigerant lines during a standard installation.
Because apparently humanity finally decided air conditioning should come with fewer existential tool requirements.
Does this system provide both heating and cooling?
Yes. The MRCOOL DIY® Select is a ductless heat pump system that provides both air conditioning and heating from a single unit.
It can cool your space during summer and provide energy-efficient heat during colder months, making it a year-round comfort solution for garages, bedrooms, additions, workshops, offices, and more.
What size room can this mini split heat pump cover?
Coverage depends on the BTU size selected, insulation quality, ceiling height, climate zone, sun exposure, and other factors.
General estimates:
- 9K BTU: Small rooms, bedrooms, offices
- 12K BTU: Medium rooms, larger bedrooms, small living areas
- 18K BTU: Garages, workshops, larger living spaces
- 24K BTU: Large garages, open-concept rooms, additions
For the best performance and efficiency, proper sizing is important.
Does the MRCOOL DIY® Select require a professional HVAC technician?
In many cases, no. The DIY® Select series is engineered for homeowner-friendly installation using pre-charged Quick Connect® technology.
However, depending on local building codes or electrical requirements, some customers may still choose to hire a licensed electrician or HVAC professional for portions of the installation.
Electricity remains very committed to consequences.
What voltage does the MRCOOL DIY® Select use?
Voltage depends on the BTU size:
- 9K and 12K models use 115V power
- 18K and 24K models use 230V power
Always verify your electrical service and breaker requirements before installation.
Is the MRCOOL DIY® Select energy efficient?
Yes. The MRCOOL DIY® Select series uses advanced inverter technology and heat pump operation to provide highly energy-efficient heating and cooling.
Compared to traditional window air conditioners or electric resistance heating, ductless inverter systems can significantly improve comfort while reducing energy consumption.
Can I control the system with my phone or WiFi?
Yes. The MRCOOL DIY® Select system supports smart control features, allowing you to adjust temperature settings, operating modes, schedules, and more using compatible WiFi/app controls.
This makes it easy to manage comfort remotely from almost anywhere.
Because naturally humans now adjust garage temperatures from grocery store parking lots. Civilization marches onward.
Is the MRCOOL DIY® Select a cold-climate heat pump?
The DIY® Select series is designed as a standard heat pump system for general residential heating and cooling applications.
It performs very well for cooling and can continue producing heat in cold outdoor temperatures, including around 0°F in many conditions. However, heating performance and efficiency will naturally decrease as temperatures drop significantly below freezing.
For customers in extremely cold climates who require maximum low-ambient heating performance, MRCOOL’s premium cold-climate systems may be a better fit.
DIY-Friendly Installation
Designed specifically for homeowners, the MRCOOL DIY system includes an installation template for the wall-mounted air handler, making it easy to place holes for refrigerant lines, cables, and drain connections accurately. The simplified design eliminates guesswork and helps you complete installation faster with confidence.
Heat Pump Technology – Heating & Cooling
The MRCOOL DIY system is a true heat pump, providing both heating and cooling in one system. It transfers heat rather than generating it, delivering highly efficient comfort year-round. The system can heat in temperatures as low as -13°F and cool in temperatures up to 122°F, keeping your home comfortable in nearly any climate.
Variable-Speed DC Inverter Compressor
The MRCOOL DIY system uses advanced DC inverter technology to continuously adjust compressor speed based on your comfort needs. Instead of constantly turning on and off like traditional systems, it runs at the optimal level to maintain temperature while using less energy. This results in lower energy costs, quieter operation, and longer system life.
Smart Control with Wi-Fi & Voice Assistants
Take full control of your comfort from anywhere using the MRCOOL SmartHVAC app on iOS or Android. Adjust temperature, monitor usage, and set automated comfort schedules. The system also integrates with Amazon Alexa and Google Assistant for convenient voice control.
No-Vac Quick Connect® Line Sets
Installation is simple thanks to MRCOOL’s patented Quick Connect® fittings. The pre-charged line sets come sealed with refrigerant and connect using basic hand tools — no vacuum pump or specialized HVAC equipment required. Just align the fittings, tighten with a wrench, and your system is ready to go.
Protected DIYPro™ Communication Cable
The MRCOOL DIYPro™ communication cable connects the indoor air handler and outdoor condenser while protecting electrical wiring inside a durable protective conduit. This heavy-duty cable helps shield wiring from weather exposure and accidental damage during installation.
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