MRCOOL® DIY® 5th Gen E Star 9,000 BTU Single Zone Mini Split Complete System with 25ft. Line Set 115V — DIY-09-HP-WM-115D25-O

Product Description 

MRCOOL DIY® 5th Gen ENERGY STAR® 9K BTU Single Zone Mini Split – The Ultimate DIY HVAC Solution

Enhance your home’s heating and cooling efficiencywith the MRCOOL DIY® 5th Gen ENERGY STAR® 9,000 BTU Single Zone Mini-Split System. Engineered for true DIY installation, this ductless heat pump mini-split is perfect for rooms up to 400 sq. ft.. With R-454B refrigerant, ENERGY STAR® certification, and smart home integration, this system provides powerful, energy-efficient performance all year round—without the need for professional installation.

Effortless DIY Installation – No HVAC Technician Required

Say goodbye to costly installations! The MRCOOL DIY® 9K BTU Mini Split comes with:

✔ Pre-Charged 25 ft. Quick Connect® Line Set – Vacuum-free, tool-free setup for easy installation.
✔ DIYPRO® Cable – Enhances safety and durability, eliminating the need for electrical conduit while protecting against outdoor elements and wildlife.
✔ Step-by-Step DIY Guide & Video Support – Get your system up and running with ease.

Install it yourself and start enjoying powerful climate control in hours—not days!

Eco-Friendly & Energy-Efficient R-454B Refrigerant

This ductless mini-split system uses R-454B refrigerant, a superior alternative to R-410A with a lower Global Warming Potential (GWP), making it a more environmentally responsible HVAC solution.

✔ ENERGY STAR® Certified – Maximizes efficiency, lowers energy bills, and reduces carbon footprint.
✔ Smart Inverter Technology – Adjusts output based on demand, improving performance and longevity.

Smart Climate Control – Comfort at Your Fingertips

Experience next-level convenience with advanced smart home integration and intelligent climate control features:

✔ Wireless Control with Smart HVAC App – Adjust temperature, mode, and settings via your smartphone (iOS & Android).
✔ Voice Control Compatible – Works with Amazon Alexa & Google Assistant for hands-free operation.
✔ Follow Me® Function – The remote acts as a thermostat, ensuring even heating and cooling based on its location.
✔ Dry Mode for Dehumidification – Removes excess moisture for improved indoor air quality and comfort.
✔ Gold Fin® Condenser – Corrosion-resistant and built to last, making it ideal for coastal and humid climates.
✔ Ultra-Quiet Operation – Enjoy whisper-quiet performance for undisturbed comfort.

Built for Durability & Reliable Performance

The MRCOOL DIY® 9K BTU Mini Split is Intertek Certified (5031495), guaranteeing industry-leading safety, efficiency, and durability.

✔ Ideal for Year-Round Use – Delivers powerful heating and cooling even in extreme temperatures.
✔ Designed for Longevity – Corrosion-resistant components protect against rust, moisture, and weather damage.

Industry-Leading Warranty – Peace of Mind Guaranteed

MRCOOL offers an unmatched warranty, ensuring long-term protection:

✔ 7-Year Compressor Warranty
✔ 5-Year Parts Warranty

WHAT'S INCLUDED

1 condenser  DIY-09-HP-C-115D25-O                                 (25ft line set with condenser)

1 wall mount air handler  DIY-09-HP-WMAH-115D25-O (com wire is with the air handler)

1 Remote and WiFi USB.                                                     (boxed with air handler)

Smart Phone NOT included.

SPECIFICATIONS & DIMENSIONS

Frequently Asked Questions

What's the difference between the 5th Gen and 4th Gen?

The 5th Gen MRCOOL DIY® Mini Split offers several key upgrades over the 4th Gen, focusing on efficiency, advanced technology, and eco-friendliness.

Here’s what’s new with the 5th Gen:

• Next-Gen R-454B Refrigerant: A more environmentally friendly refrigerant with lower global warming potential (GWP), compliant with the latest HVAC regulations.
• Higher Energy Efficiency: Improved SEER2 ratings for greater energy savings and optimized performance.
• Enhanced System Reliability: Upgraded components for better heating and cooling performance.
  
  

Can I install it myself, or do I need a professional?

The MRCOOL DIY system is designed for homeowners and doesn’t require HVAC tools. You can install the indoor and outdoor units yourself using the pre-charged Quick Connect® lines. However, a licensed electrician is required for the electrical hookup to ensure safety and code compliance.

Does it work in cold weather?
Yes. MRCOOL 5th Gen systems feature low-ambient heating and can provide reliable heat even when outdoor temperatures drop to around 5°F.

How do I know what BTU size I need for my rooms?

A general rule of thumb is 20 BTU per square foot of space. Here's a rough guide:

• 6,000 BTU = 100 - 150 sq ft
• 9,000 BTU = 150 - 350 sq ft
• 12,000 BTU = 351- 500 sq ft
• 18,000 BTU = 501 – 750 sq ft
• 24,000 BTU = 751 – 1,000 sq ft
• 36,000 BTU = 1,001 - 1,500 sq ft

Some additional factors may impact performance such as insulation, ceiling height, sun exposure and the number of appliances in the room. For assistance, contact our Product Experts

Does it heat as well as cool?

Yes. All 5th Gen models are heat pumps, providing both heating and cooling for year-round comfort.

Is it Wi-Fi compatible?

Yes. The MRCOOL SmartHVAC app allows smartphone control and works with Amazon Alexa and Google Assistant.

What is the warranty?

The MRCOOL 5th Generation DIY Mini-Split systems offer the following warranty coverage:

• 7-Year Compressor Replacement Warranty: This warranty ensures that if the compressor fails within the first seven years, MRCOOL will provide a replacement.
• 5-Year Parts Warranty: This warranty covers all parts of the system for five years from the date of purchase.

Recommended Room Types

Perfect for:

• Bedrooms
• Home offices
• Small living rooms
• Tiny homes
• Garages
• Bonus rooms
• Apartments
• Sunrooms

Why Buy from MRCOOL  Direct?

As the most trusted independent MRCOOL dealer in the USA, we provide:

✅ Factory-Direct Pricing – Get the best deals on genuine MRCOOL systems.
✅ Fast & Secure Shipping – Reliable delivery across the USA.
✅ Expert DIY Support – Our team is here to help with installation and troubleshooting.

Upgrade to the MRCOOL DIY® 5th Gen ENERGY STAR® 9K BTU Mini Split Today!

Order now and enjoy powerful, efficient, and easy-to-install heating and cooling—designed specifically for DIYers like you! 

MRCOOL® 5th Gen DIY vs Easy Pro™ 5th Gen — Which Mini-Split Is the Better Choice?

When you’re investing in a ductless mini-split system, you’re not just buying equipment—you’re buying comfort, reliability, energy savings, and warranty protection for the next decade or more.

MRCOOL® gives homeowners two powerful options: the 5th Generation DIY Series and the Easy Pro™ 5th Gen Series.

Both are designed to simplify installation and deliver efficient year-round comfort, but they are built for different types of customers and use cases.

Below is a straight-forward, expert breakdown so you can choose the system that fits your home, budget, and expectations.

1. Installation: DIY Game-Changer vs Semi-DIY Convenience

MRCOOL® 5th Gen DIY — The Only True DIY Mini-Split

The 5th Gen DIY is the industry-leading* self-installation mini-split system.

It uses MRCOOL’s pre-charged QuickConnect® line sets, filled at the factory with R-454B refrigerant.

• No vacuum pumps
• No gauges
• No refrigerant handling
• No HVAC license 

Simply connect, tighten, and you’re done.

This technology is why the DIY Series is unmatched in the entire HVAC market.

Comes standard with:

• 25 ft QuickConnect® line set (extendable)
• R-454B refrigerant pre-charged
• Tools-free refrigerant system

This system can be installed in about 3–5 hours with common household tools.

MRCOOL® Easy Pro™ 5th Gen — Easier Than Traditional Systems

The Easy Pro™ uses a 16 ft Fast Connection pre-charged line set, also using R-454B.

This makes Easy Pro ideal for:

• Apartments
• Rental properties
• Light commercial installs
• Homeowners who want professional sign-off

Bottom line:

• DIY 5th Gen = No HVAC professional required
• Easy Pro 5th Gen = Very simplified install, but requires a technician 

2. Energy Efficiency: The 5th Gen DIY Wins

Both systems are efficient, but the 5th Gen DIY is the performance champion.

5th Gen DIY 9K BTU

• 23.6 SEER2
• One of the most efficient ductless DIY systems available today
• Lower monthly energy use = lower operating cost for life of the unit

This matters in real dollars:

• More comfort for less energy
• Better humidity control
• Faster heating and cooling
• Higher performance in extreme climates

Easy Pro 9K BTU

• 20.2 SEER2
• Still excellent vs traditional mini-splits
• Ideal for moderate climates and budget installations 

Efficiency takeaway:

If you want the lowest energy bills, the 5th Gen DIY is the clear winner.

3. Warranty Protection: The Biggest Difference

Here’s where MRCOOL separates casual systems from premium investment-grade HVAC.

MRCOOL® 5th Gen DIY Warranty

• 7-Year Compressor
• 5-Year Parts

This is industry-defining coverage—unmatched by any competitor in the DIY space.

It shows MRCOOL’s confidence in the engineering of their flagship product.

MRCOOL® Easy Pro Warranty

• 2-Year Compressor
• 1-Year Parts
• Registration required

It offers solid protection, but nowhere near the level of the DIY Series.

If long-term reliability matters to you — choose 5th Gen DIY.

4. Smart Features & App Control

Both systems deliver advanced comfort, but the 5th Gen DIY includes more premium features.

5th Gen DIY:

• Voice control (Alexa / Google Assistant)
• Follow Me comfort sensor
• Advanced inverter technology
• Higher cold climate performance
• Better humidity and noise reduction

Easy Pro:

• Quiet operation
• Basic app and smart features
• Excellent temperature stability

If you want technology that feels luxury, the DIY Series is a step above.

5. Line Set Length: Flexibility Matters

Space planning is a real-world problem.

DIY 5th Gen

• Standard 25 ft
• Expandable with extensions
• Perfect for multi-room or attic/basement runs
• Great for coastal or large properties

Easy Pro

• Standard 16 ft
• Fits small rooms, garages, and simple layouts 

Longer lines = more flexibility and fewer compromises. 

Which One Should You Choose?

 Choose MRCOOL® 5th Gen DIY if you want:

• True homeowner installation — no HVAC tech required
• 23.6 SEER2 efficiency or higher
• Lower monthly energy bills
• Stronger long-term reliability
• Lifetime system warranty
• 25 ft line set flexibility
• Premium smart features
• Coastal-grade durability

This is the flagship MRCOOL system.

If you want the best performance and future-proof value, choose DIY 5th Gen.

Choose MRCOOL® Easy Pro if you want:

• MRCOOL quality at a lower entry price
• If you want shorter line lengths (16 ft)
• A simpler installation than traditional systems
• Quiet comfort without high-end features
• Solid performance for smaller rooms or secondary spaces
• You plan to use a professional installer

This is the budget-friendly way to get MRCOOL performance.

The Bottom Line

Both the MRCOOL® Easy Pro™ and 5th Gen DIY mini-splits deliver real comfort, inverter technology, and simple installation.

But they are not the same class of product:

• MRCOOL® 5th Gen DIY = Premium performance, best-in-class efficiency, and industry-leading warranties.
• MRCOOL® Easy Pro™ = A more affordable way to upgrade comfort with simplified installation.

 If you want maximum efficiency, reliability, smart features, and the strongest warranty in HVAC, the 5th Gen DIY stands alone.

If you need solid performance at a lower cost, and you don’t mind a less warranty protection, the Easy Pro is the perfect fit.

Need help sizing the right capacity (9K, 12K, 18K, 24K+)?

Call us MRCOOL DIRECT we’ll get you matched correctly—fast, accurate, and homeowner-friendly.