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

MRCOOL DIY® 9K BTU 5th Gen Single-Zone Mini Split System

The MRCOOL DIY® 5th Generation 9,000 BTU Single-Zone Mini Split System provides efficient, reliable heating and cooling for spaces up to approximately 400 square feet. Designed for homeowners who want professional-level performance without professional installation, this system delivers year-round comfort with true DIY simplicity.

Looking for a 6,000 BTU Single-Zone Mini Split?

MRCOOL does not manufacture a 6K BTU single-zone DIY system. However, this 9K BTU 5th Gen system is inverter-driven, meaning it automatically adjusts its output based on demand.

Unlike traditional fixed-capacity systems, the MRCOOL 9K can modulate down to lower operating levels, making it an ideal solution for spaces that would traditionally be sized at 6,000 BTU.

If you're searching for:

• 6k mini split
• 6000 BTU single zone mini split
• 6,000 BTU DIY mini split
• small room mini split system

This 9K inverter system is the correct modern replacement and provides greater efficiency, better humidity control, and improved temperature stability.

Built on MRCOOL’s proven DIY platform, the system uses MRCOOL® DIY® Quick Connect Pre-Charged Line Sets, allowing installation without vacuum pumps, refrigerant handling, or specialized HVAC tools. All critical components arrive factory sealed and pre-charged, making installation accessible for anyone comfortable using basic tools.

Advanced inverter technology helps maintain consistent indoor temperatures while reducing energy consumption. This system is ENERGY STAR® certified and uses R-454B refrigerant, a lower-GWP alternative to R-410A that meets modern efficiency and environmental standards without sacrificing performance.

Comfort control is flexible and intuitive. The system supports wireless remote operation, app-based control through the MRCOOL Smart HVAC app, and voice control via Amazon Alexa and Google Assistant. Features such as Follow Me temperature sensing and Dry Mode dehumidification allow precise comfort adjustments throughout the year.

Designed for durability, the outdoor condenser features Gold Fin® corrosion-resistant coating, making it suitable for coastal or high-humidity environments. Quiet operation makes this system ideal for bedrooms, home offices, and other noise-sensitive spaces. When properly registered, the system is backed by manufacturer warranty coverage for added peace of mind.

This system is an excellent solution for bedrooms, small living areas, offices, and additions where efficient climate control, smart features, and DIY installation are priorities.

Specifications & Dimensions

At MRCOOL DIY Direct, we understand that every home is different, and that the standard 25-foot pre-charged line set included with MRCOOL DIY systems may not fit every installation. That’s why we offer a range of longer and customizable line set options, making it easier for you to get exactly what you need — without extra hassle or unnecessary parts.

How Our Line Set Options Work:

• Standard System:
  Every system from MRCOOL comes factory-bundled with a 25' pre-charged line set and 25' of control wire.

• Choosing an Alternate Length:
  If you select a different line set length (such as 16', 35', 41', 50', or 75'):

  • Your order will be custom-bundled individually at our warehouse.

  • This process typically adds 1–2 extra business days for preparation and shipping.

  • You will receive the exact pre-charged line set footage you requested — either as a single line set or a combination of two line sets (if needed) to achieve the proper length.

📦 Important Details to Know:

• Single vs Combined Lengths:

  • 16': Factory 25' is swapped for a 16' pre-charged line set.

  • 35': A single 35' pre-charged line set is provided.

  • 41': Combines your standard 25' line set with an additional 16' line set + supplied coupler + extended control wire.

  • 50': A continuous 50' pre-charged line set is provided with longer control wire.

  • 75': Combines a 25' + 50' pre-charged line set with couplers and 75' of extended control wire.

• Control Wire Upgrade:
  Any time your line set length exceeds 25', you will receive a new longer control wire matched to the total length.

  We never recommend splicing control wires. These systems are essentially computers — shielded, continuous control cable ensures no interference, no corrosion, and no installation headaches down the road.

Why Shoppers Trust MRCOOL DIY Direct:

Unlike big-box retailers that sell you a one-size-fits-all kit (and leave you hunting for missing parts), we custom-configure your system so you have everything you need from the start.

• No extra trips to the hardware store.
• No guessing which coupler or cable you need.
• No surprises during installation.

With years of experience specializing in DIY HVAC systems, MRCOOL DIY Direct has earned a reputation as the USA's most trusted independent HVAC dealer.
We are committed to making DIY HVAC installation simple, affordable, and frustration-free — and our custom line set bundling is just one more way we deliver on that promise.

Need help choosing the right line set length for your project?
Contact our expert team today — we’re here to help you get it done right the first time!