MRCOOL® 12k DIY 5th Generation Mini-split Air Handler 115v

MODEL: DIY-12-HP-WMAH-115D25-O

Powerful, Ultra-Quiet Comfort for Spaces up to 550 sq. ft.

The MRCOOL® 12k BTU DIY® 5th Generation Mini-Split Air Handler offers efficient, whisper-quiet heating and cooling designed for easy, do-it-yourself installation. Perfect for bedrooms, offices, and medium-sized living spaces up to 550 sq. ft., this unit pairs seamlessly with your MRCOOL® DIY® 5th Gen Single-Zone or Multi-Zone Condenser.

Featuring a pre-charged 25-foot Quick Connect® line set filled with eco-friendly R-454B refrigerant, this system eliminates the need for vacuum pumps or professional HVAC installation. The included DIYPro™ Communication Cable replaces traditional electrical conduit, offering durability against outdoor elements.

Control your climate effortlessly with the SmartHVAC® app, Amazon Alexa, or Google Assistant voice commands. The built-in Follow Me® function senses the temperature at the wireless remote’s location, maintaining your ideal comfort level.

Built for long-lasting performance, the Gold Fin® corrosion-resistant coating makes this air handler ideal for coastal or humid environments. Enjoy dependable, efficient, year-round comfort backed by one of the industry’s leading warranties.

Why You’ll Love It

✅ Perfect for Medium Spaces — Ideal for bedrooms, home offices, and dens up to 550 sq. ft.
✅ True DIY Installation — Quick Connect® line sets and DIYPro™ cable make setup simple — no HVAC pro required
✅ Smart-Home Ready — Wi-Fi enabled, compatible with SmartHVAC® app, Alexa, and Google Assistant
✅ Follow Me® Personal Comfort — Wireless remote tracks your location to deliver customized comfort
✅ Ultra-Quiet Operation — Peaceful performance as low as 18 dBA
✅ Gold Fin® Protection — Anti-corrosion coating ensures durability in tough climates
✅ All-Season Heating & Cooling — Operates from 5°F to 86°F, delivering comfort year-round
✅ Industry-Leading Warranty — Limited Lifetime Compressor Warranty (with registration), 7-Year Compressor, 5-Year Parts

What’s Included:

MRCOOL® 12K 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	115V
Phase	1
Cycle	60 Hz
Mount Type	Wall-Mounted
Color	White
Max Coverage Area	Up to 550 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)	31.57" x 11.69" x 7.44"
Gross Dimensions (WxHxD)	36.02" x 14.37" x 16.34"
Net Weight	24.91 lbs
Gross Weight	35.49 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.

Why You’ll Love It

Specifications at a Glance

Attribute

Details

Voltage

115V

Phase

Cycle

60 Hz

Mount Type

Wall-Mounted

Color

White

Max Coverage Area

Up to 550 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)

31.57" x 11.69" x 7.44"

Gross Dimensions (WxHxD)

36.02" x 14.37" x 16.34"

Net Weight

24.91 lbs

Gross Weight

35.49 lbs

Contains Electronics / Chemicals / Compressed Gas

Yes

Proposition 65 Warning

Yes

Installation & Guides

Room Size & BTU Coverage Guide

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.

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 Policy

free curbside delivery

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:

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.