MRCOOL DIY® 5th Gen E-Star 18K BTU (1.5 Ton) Ceiling Cassette Mini Split Heat Pump – 21.5 SEER2
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MRCOOL DIY 5th Gen E-Star Series 18K BTU, 1.5 Ton, 21.5 SEER2 Ductless Mini-Split Heat Pump System with Ceiling Cassette Air Handler – R-454B
The MRCOOL DIY 5th Gen E-Star Series 18K BTU Mini-Split Heat Pump System delivers next-generation efficiency, low environmental impact, and true do-it-yourself installation. This single-zone package features a premium ceiling cassette air handler for discreet comfort, providing powerful heating and cooling performance without compromising aesthetics.
Unlike traditional wall-mounted units, the MRCOOL ceiling cassette fits neatly between standard 16” ceiling joists, making it the perfect low-profile solution for modern homes and office spaces. This system uses MRCOOL’s latest R-454B refrigerant, offering a lower Global Warming Potential (GWP) and compliance with updated refrigerant regulations.
💡 What’s Included in This Bundle?
✔ MRCOOL DIY 5th Gen 18K BTU, 1.5 Ton, 21.5 SEER2 Heat Pump Condenser
(Model: DIY-18-HP-C-230C)
✔ MRCOOL DIY 5th Gen 18K BTU Ceiling Cassette Air Handler
(Model: DIYCASSETTE18HP-230C25)
✔ Standard 25 Ft. MRCOOL Pre-Charged Quick Connect Line Set – R-454B
(No vacuum or special tools required)
💬 Need a longer line set?
This system comes standard with a 25' pre-charged line set. You can upgrade to a 35' continuous line set with matching control wire for installations requiring a bit more reach without added connections.
For even greater flexibility, extended configurations are also available in 41', 50', or 75' total line lengths. These setups use the included 25' pre-charged line set paired with an additional pre-charged line set connected via MRCOOL Quick Connect® couplers, along with a longer control wire.
This sectional or continuous approach provides easy installation options for every scenario—from simple straight runs to complex or tight routing—while maintaining MRCOOL’s leak-proof reliability and DIY simplicity.
🌡️ MRCOOL 5th Gen Heat Pump Condenser – Key Features
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18,000 BTU Output – Ideal for heating & cooling single-zone spaces up to ~750–800 sq ft
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21.5 SEER2 High Efficiency – Lower utility costs without sacrificing performance
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Pre-Charged with R-454B Refrigerant – Eco-friendly, low-GWP refrigerant
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Gold Fin Condenser Coating – Corrosion-resistant for long outdoor life
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Cold Weather Ready – Operates in temperatures down to 5°F
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True DIY Installation – Quick Connect fittings, no vacuum pump needed
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Warranty – 7-Year Compressor / 5-Year Parts (Lifetime Limited Compressor with registration)
🔲 MRCOOL Ceiling Cassette Air Handler – 18K BTU
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Flush Ceiling Installation – Fits between 16” joists for a seamless appearance
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Multiple Comfort Modes – FAN ONLY, QUIET, SLEEP, AUTO for complete control
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Elevating Air Filter System – Drops up to 4.9 ft for easy, tool-free cleaning
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Unified Aesthetic – Matches MRCOOL multi-zone cassette design
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Smart Home Ready – Wi-Fi enabled, works with Alexa & Google Assistant
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Expandable Design – Visually matches multi-zone setups for future expansion
🔧 Why Choose MRCOOL DIY 5th Gen?
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No HVAC License Required – Perfect for homeowners & skilled DIYers
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R-454B Refrigerant Compliant – Ready for new HVAC regulations
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Pre-Charged Line Sets – No refrigerant handling or vacuuming
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Energy Efficient – Meets or exceeds ENERGY STAR® guidelines
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Nationwide Support & Fast Shipping – Buy from the #1 Independent MRCOOL Dealer: MRCOOL DIY Direct
🛒 Order Your MRCOOL 5th Gen DIY Ceiling Cassette System Today!
Experience discreet, high-efficiency climate control you can install yourself. Whether you’re upgrading a bedroom, home office, or guest suite, this 5th Gen DIY mini-split is built for performance, convenience, and compliance.
🔗 Shop now at MRCOOL DIY Direct – stay cool and save the smart, easy way.
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DIY Single-Zone System Cassette
Outdoor Condenser
DIY Ceiling Cassette
Pre-Charged DIY Line Set
Control Wire
Wireless Remote
WiFi Dongle / Smart Controller Adapter
Wall Sleeve / Wall Pass-Through
Line Set Wrap / Insulation Tape
Installation Manual
DIY Quick-Connect Adapters
Download installation manuals, spec sheets, and warranty documents for this system.
- E-Star Hybrid Ducted Air Handler Install Manual
- E-Star Ceiling Cassette Service Manual
- E-Star Ceiling Cassette Product Brochure
- E-Star Ceiling Cassette Installation Manual
- E-Star Ceiling Cassette Performance Data
- DIY Ceiling Cassette Air Handler (18K BTU) AHRI
- 5th Gen E-Star® Series Smart Controller Manual
- 5th Gen E-Star® Series Remote Control Guide
- 5th Gen E-Star® Series Quick Start Guide
- 5th Gen E-Star® Series Product Brochure
Is professional installation required for the E-Star series?
Is professional installation required for the E-Star series?
Does the E-Star include a pre-charged line set?
Does the E-Star include a pre-charged line set?
What refrigerant does the E-Star use?
What refrigerant does the E-Star use?
Does the E-Star system still cool efficiently in summer?
Does the E-Star system still cool efficiently in summer?
Why does the E-Star cost more than standard mini-split systems?
Why does the E-Star cost more than standard mini-split systems?
Is the E-Star a good choice as a primary heat source?
Is the E-Star a good choice as a primary heat source?
How well does the E-Star perform in cold weather?
How well does the E-Star perform in cold weather?
What makes the E-Star different from other MRCOOL mini-split systems?
What makes the E-Star different from other MRCOOL mini-split systems?
Is the E-Star suitable for off-grid or backup heating scenarios?
Is the E-Star suitable for off-grid or backup heating scenarios?
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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.
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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