MRCOOL® 18k DIY 5th Generation Mini-split Air Handler 230v

MODEL: DIY-18-HP-WMAH-115D25-O

Powerful, Ultra-Quiet Comfort for Spaces up to 1,000 sq. ft.

The MRCOOL® 18k BTU DIY® 5th Generation Mini-Split Air Handler delivers high-capacity, whisper-quiet heating and cooling designed for hassle-free, do-it-yourself installation. Perfect for large bedrooms, open-concept living rooms, basements, and studios up to 1,000 sq. ft., this air handler pairs seamlessly with your MRCOOL® DIY® 5th Gen Single-Zone or Multi-Zone Condenser.

The pre-charged 25-foot Quick Connect® line set comes filled with eco-friendly R-454B refrigerant, eliminating the need for vacuum pumps or professional HVAC installation. Included DIYPro™ Communication Cable replaces bulky electrical conduit while standing up to the elements.

Effortlessly control your home’s climate through the SmartHVAC® app, Amazon Alexa, or Google Assistant voice commands. The built-in Follow Me® function ensures your room stays at your ideal temperature by sensing the remote’s location.

Protected with Gold Fin® anti-corrosion coating, this unit is made for long-lasting performance, even in coastal and humid climates. Enjoy year-round heating and cooling backed by one of the best warranties in the HVAC industry.

Why You’ll Love It

✅ Ideal for Mid-to-Large Spaces — Perfect for open-plan areas, large bedrooms, and living rooms up to 1,000 sq. ft.

✅ True DIY Installation — No HVAC license or vacuum pump needed with Quick Connect® line sets and DIYPro™ cable.

✅ Smart Home Compatible — Wi-Fi enabled, works with SmartHVAC® app, Alexa, and Google Assistant.

✅ Follow Me® Technology — Maintains precise comfort based on your remote’s location.

✅ Ultra-Quiet Operation — As low as 24 dBA for a peaceful, uninterrupted environment.

✅ Gold Fin® Condenser Protection — Rust-resistant coating built for coastal conditions.

✅ All-Season Heating & Cooling — Effective operation from 5°F to 86°F, for true year-round comfort.

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

What’s Included:

MRCOOL® 18K DIY® 5th Gen Mini-Split Air Handler
25ft DIYPro™ Communication Cable
Wireless Remote Control
Installation Accessories
MRCOOL® Warranty

Specifications

Specifications at a Glance

Attribute	Details
Voltage	208/230V
Phase	1
Cycle	60 Hz
Mount Type	Wall-Mounted
Color	White
Max Coverage Area	Up to 1,000 sq. ft.
Oscillation	Yes
Filter Type	Reusable
Auxiliary Heater	Not Included
Fan Only Option	Yes
Quiet Mode	Yes
Auto Cool	Yes
Wi-Fi Enabled	Yes
App Compatibility	iOS & Android
Remote Control Included	Yes
Batteries Included	Yes
UL/ETL Listed	Yes
AHRI Certified	Yes
Warranty	Lifetime Limited*, 7-Year Compressor, 5-Year Parts
Net Dimensions (WxHxD)	42.52" x 13.19" x 8.90"
Gross Dimensions (WxHxD)	46.06" x 15.75" x 18.50"
Net Weight	33.95 lbs
Gross Weight	49.60 lbs
Contains Electronics / Chemicals / Compressed Gas	Yes
Proposition 65 Warning	Yes

Installation

Installation & Guides

Product Brochure

Installation Manual

Remote Control Manual

Warranty Document

Room Size & BTU Coverage Guide

Choosing the right BTU (British Thermal Unit) output ensures your space stays consistently comfortable all year round. Use this quick reference chart to match your room size with the recommended cooling and heating capacity.

BTU Rating	Ideal Room Size
9,000 BTU	250 – 400 sq. ft.
12,000 BTU	400 – 600 sq. ft.
18,000 BTU	600 – 1,000 sq. ft.
24,000 BTU	1,000 – 1,300 sq. ft.
36,000 BTU	1,300 – 1,800 sq. ft.

Important: Always consider additional factors like ceiling height, insulation, sun exposure, and the number of heat-generating appliances when selecting your system. Still unsure? Our experts are just a message away to help guide you.

What You Need for a Complete System

For full heating and cooling performance, pair this indoor air handler with:

MRCOOL® DIY® 5th Gen Single-Zone Condenser (115V Compatible)
MRCOOL® Quick Connect® Pre-Charged Line Set (25ft included)
DIYPro™ Communication Cable (25ft included)

Optional Accessories:

MRCOOL® Wall Mount Bracket
Additional Quick Connect® Line Sets (for extended runs)
Coupler Kits (for line set extensions)

Important:
This air handler requires connection to a compatible MRCOOL® DIY® 5th Gen Condenser. It is not compatible with 3rd or 4th Gen systems.

Shipping & Returns

Shipping Policy

At Cool Heat Direct, we offer free curbside delivery on all MRCOOL product orders via FedEx Ground, FedEx Freight, or trusted carriers depending on order size.

Deliveries are made to the curbside — please arrange assistance for heavy or large items, as drivers do not carry items indoors or upstairs.
Tracking details will be sent within 3–5 business days after placing your order.
Freight shipments are scheduled directly by the carrier using the contact information you provide at checkout.
Please inspect your shipment upon delivery and report any visible damage on the delivery receipt.

Return Policy

We want you to love your purchase from Cool Heat Direct. If you need to return an item:

Contact us within 30 days of delivery.
Items must be unused, uninstalled, and in their original packaging.
A 35% restocking fee applies to all approved returns.
Accessories such as line sets, wall mounts, and couplers are non-returnable.
Return shipping is the customer’s responsibility unless the item is damaged or defective on arrival.

To start a return, please email us at support@coolheatdirect.com with your order number and reason for return.