MODEL: DIY-09-HP-WMAH-230D25-O

Powerful, Whisper-Quiet Comfort for Spaces up to 400 sq. ft.

The MRCOOL® 9k BTU DIY® 5th Generation Mini-Split Air Handler delivers powerful, energy-efficient, and fully DIY-friendly heating and cooling — ideal for medium-sized bedrooms, home offices, compact living rooms, or bonus rooms up to 400 sq. ft.

This ductless, wall-mounted air handler pairs easily with your MRCOOL® DIY® 5th Gen Multi-Zone Condenser, offering professional-grade performance without professional tools. Thanks to the pre-charged 25-foot Quick Connect® line set and eco-friendly R-454B refrigerant, installation is clean, fast, and hassle-free — no vacuum pump or gauges required.

Enjoy effortless control via the SmartHVAC® app, Amazon Alexa, or Google Assistant, and let Follow Me® technology adjust the temperature based on your location for room-to-room comfort that follows you.

Protected by Gold Fin® corrosion-resistant coating and backed by an industry-leading warranty, this unit ensures lasting, worry-free performance in any season.

Why You’ll Love It

Perfect for Medium Spaces — Ideal for bedrooms, offices, dens, and bonus rooms up to 400 sq. ft.

Simple DIY Installation — Pre-charged Quick Connect® lines and included 25ft DIYPro™ Communication Cable mean no vacuuming, gauges, or HVAC pro required.

Smart-Home Compatible — Wi-Fi enabled for easy control via the SmartHVAC® app, Alexa, or Google Assistant.

Follow Me® Comfort Technology — Automatically adjusts based on your exact location for precise, personal comfort.

Ultra-Quiet Performance — Operates between 27 and 40 dBA for peaceful, low-noise operation.

Gold Fin® Protection — Corrosion-resistant coating extends system durability.

Year-Round Efficiency — Cools down to 5°F and heats up to 86°F, delivering dependable comfort in any season.

Industry-Leading Warranty — Limited Lifetime Compressor Warranty (with registration), 7-Year Compressor, and 5-Year Parts Warranty.

What’s Included:

  • MRCOOL® 9K DIY® 5th Gen Mini-Split Air Handler

  • 25ft DIYPro™ Communication Cable

  • Wireless Remote Control

  • Installation Accessories

  • MRCOOL® Warranty

Questions, answered

Everything homeowners ask before buying a MRCOOL® system.

Installation

Do I need an HVAC technician to install this?

No. MRCOOL® DIY systems are designed for homeowner installation. The pre-charged Quick Connect® line set means there's no refrigerant handling, no vacuum pump, and no special tools or license required.

How long does installation take?

Most single-zone systems go in within a few hours: mount the indoor air handler, set the outdoor condenser, connect the pre-charged line set, and power it on.

Do I need an electrician?

The system needs a dedicated circuit. Most homeowners have a licensed electrician add the breaker and disconnect — everything else you can do yourself.

Sizing & compatibility

What BTU size do I need?

As a rule of thumb: up to 400 sq ft → 9–12K BTU, 400–600 sq ft → 12–18K, 600–1,000 sq ft → 18–24K. Use the room-size guide above and factor in insulation, ceiling height and sun exposure.

Will it heat in winter?

Yes — these are heat pumps, so they heat and cool. Many MRCOOL® systems keep heating in sub-freezing temperatures; check each model's spec sheet for its low-temperature heating range.

115V or 230V — which do I need?

9K–12K units are usually 115V (standard outlet circuit); 18K and larger are typically 230V. The voltage is shown in the product options and specifications.

Warranty & support

What warranty is included?

MRCOOL® systems carry manufacturer warranty coverage — typically 5–10 years on major components when you register your system after installation.

How do I get help choosing or installing?

Email support@coolheatdirect.com — our U.S. team replies within one business day with sizing, voltage and compatibility help.

Shipping & returns

How fast does it ship?

Most products ship in 3–5 business days with free curbside delivery in the continental U.S. The freight carrier calls to schedule your delivery.

Can I return it?

Returns are accepted within 30 days on new, unopened items in original packaging. A restocking fee may apply to HVAC equipment — we always confirm before issuing a return authorization.

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