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
[E-Star] Is professional installation required for the E-Star series?
[E-Star] Is professional installation required for the E-Star series?
[E-Star] Does the E-Star include a pre-charged line set?
[E-Star] Does the E-Star include a pre-charged line set?
[E-Star] What refrigerant does the E-Star use?
[E-Star] What refrigerant does the E-Star use?
[E-Star] Does the E-Star system still cool efficiently in summer?
[E-Star] Does the E-Star system still cool efficiently in summer?
[E-Star] Why does the E-Star cost more than standard mini-split systems?
[E-Star] Why does the E-Star cost more than standard mini-split systems?
[E-Star] Is the E-Star a good choice as a primary heat source?
[E-Star] Is the E-Star a good choice as a primary heat source?
[E-Star] How well does the E-Star perform in cold weather?
[E-Star] How well does the E-Star perform in cold weather?
[E-Star] What makes the E-Star different from other MRCOOL mini-split systems?
[E-Star] What makes the E-Star different from other MRCOOL mini-split systems?
[E-Star] Is the E-Star suitable for off-grid or backup heating scenarios?
[E-Star] 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.