What's in the box
- 1 × MRCOOL® DIY® 5th Gen 12K BTU Wall-Mounted Air Handler
- 1 × Wireless Remote Control
- Product Documentation
- DIY-friendly when installed as part of a compatible MRCOOL® DIY® 5th Gen system.
- This indoor air handler must be wall-mounted and connected to a compatible MRCOOL® outdoor condenser using approved Quick Connect® components.
- Electrical requirements, permits, and local building codes may vary.
- Professional electrical work may be required.
- Base Parts Warranty: 5 Years
- Base Compressor Warranty: 7 Years
- Eligible for the MRCOOL® Care Program when installed and registered as part of a qualifying MRCOOL® DIY® 5th Gen system.
Warranty coverage may depend on proper installation, compatible system pairing, product registration, and MRCOOL® warranty requirements. Please refer to the product warranty documentation for full terms, eligibility, and coverage details.
- Free U.S. curbside delivery within the Lower 48 States on qualifying orders
- Orders ship from U.S. warehouse locations
- Delivery times may vary by destination, product availability, and carrier scheduling
- Returns are accepted within 30 days for unused, uninstalled products that meet return eligibility requirements
- Approved returns may be subject to a restocking fee
MODEL: DIY-12-HP-WMAH-230D25-O
Comfort for Medium Rooms and Everyday Living Spaces.
Need efficient heating and cooling for a master bedroom, larger office, guest room, studio, or mid-size living area?
The MRCOOL® DIY® 5th Gen 12K BTU Wall-Mounted Air Handler is designed to deliver reliable comfort in rooms up to around 550 sq ft when paired with a compatible MRCOOL® DIY® 5th Gen multi-zone condenser.
This indoor air handler gives your room its own comfort zone, allowing you to control temperature, airflow, quiet mode, fan-only operation, dry mode, and smart settings from the included remote or through app-based control.
Built for MRCOOL® DIY® 5th Gen multi-zone systems, this 230V wall-mounted air handler features a clean white design, reusable filter, Follow Me® comfort sensing, WiFi compatibility, and smart-home control through Amazon Alexa and Google Assistant.
Smart. Efficient. Flexible. Built for everyday room comfort.
Why You’ll Love It
✅ 12K BTU wall-mounted air handler
✅ Ideal for rooms up to around 550 sq ft
✅ Designed for compatible MRCOOL® DIY® 5th Gen multi-zone systems
✅ Clean white wall-mounted design
✅ WiFi and app compatible
✅ Works with Amazon Alexa and Google Assistant
✅ Follow Me® comfort sensing
✅ Quiet Mode for lower sound comfort
✅ Auto Cool and Fan Only options
✅ Reusable filter
✅ Remote control included
✅ DIYPRO® cable compatible
✅ 5-Year Parts / 7-Year Compressor base warranty coverage when used as part of an eligible system
Best For
Master Bedrooms • Larger Bedrooms • Home Offices • Guest Rooms • Studios • Mid-Size Living Areas • Multi-Zone Mini-Split Systems • MRCOOL® DIY® 5th Gen Installations
What You Need for a Complete System
This product is an indoor air handler only.
For full heating and cooling performance, this air handler must be paired with compatible MRCOOL® DIY® 5th Gen multi-zone equipment.
Required for a complete system:
- MRCOOL® DIY® 5th Gen Multi-Zone Condenser — powers the system and connects multiple indoor zones.
- MRCOOL® Quick Connect® Pre-Charged Line Set — connects the indoor air handler to the outdoor condenser.
- DIYPRO® Cable — supports communication between the indoor air handler and outdoor condenser.
Wireless Remote Control — included with the air handler for room-by-room comfort control.
Optional accessories:
- MRCOOL® Wall Mount Bracket
- Additional Quick Connect® Line Sets
- Coupler Kits, if line set extension is required
Important: This air handler is not a stand-alone unit. It requires a compatible MRCOOL® DIY® 5th Gen multi-zone condenser for operation.
Compatibility note: This air handler is not compatible with MRCOOL® 3rd or 4th Generation systems.
| Product Type | Air Handler |
| Series | DIY® 5th Gen |
| BTU Size | 12K BTU |
| Voltage | 230V |
| Mount Type | Wall Mounted |
| Coverage | 550 sq ft |
| Model | DIY-12-HP-WMAH-230D25-O |
| Brand | MRCOOL® |
| System Type | Multi-Zone |
| Unit Type | Indoor Unit |
| Color | White |
| Phase | 1 Phase |
| Cycle | 60Hz |
| Full Voltage | 208/230V |
| Oscillation | Yes |
| Filter Type | Reusable |
| Quiet Mode | Yes |
| Auto Cool | Yes |
| Fan Only | Yes |
| WiFi Control | Yes |
| App Control | Yes |
| iOS Support | Yes |
| Android Support | Yes |
| Voice Control | Alexa / Google |
| Remote Control | Included |
| Aux Heater | No |
| Heat Kit | No |
| Batteries | Yes |
| Electronics | Yes |
| Chemicals | Yes |
| Aerosol | Yes |
| Gas Content | Yes |
| Prop 65 | Yes |
| UL Listed | Yes |
| ETL Listed | Yes |
| AHRI Certified | Yes |
| Intertek Listed | 5031495 |
| Base Warranty | 5-Year Parts / 7-Year Compressor |
| Net Dimensions | 31.57" W × 11.63" H × 7.44" D |
| Net Weight | 24.47 lb |
| Gross Dimensions | 36.02" W × 14.37" H × 16.34" D |
| Gross Weight | 35.05 lb |
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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