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Description
MRCOOL DIY 18K Hyper Heat Mini Split System – 5th Gen, -22°F Heating, 21.2 SEER2, Pre-Charged DIY Line SetMRCOOL DIYHH 18 Hyper Heat 18K Mini Split System with Wall Mount Air Handler The MRCOOL DIYHH 18 Hyper Heat 18K Mini Split System is a 5th Generation DIY ductless heat pump designed for homeowners who need reliable heating and cooling in true cold climate conditions. This complete 18,000 BTU single zone bundle includes the DIYHH 18 outdoor condenser, the DIY 18 HP WMAH 230D25 O wall mounted air handler, a 25 ft QuickConnect pre charged line set, and
MRCOOL DIYHH-18 Hyper Heat 18K Mini Split System with Wall Mount Air Handler
The MRCOOL® DIYHH-18 Hyper Heat 18K Mini Split System is a 5th Generation DIY ductless heat pump designed for homeowners who need reliable heating and cooling in true cold-climate conditions. This complete 18,000 BTU single-zone bundle includes the DIYHH-18 outdoor condenser, the DIY-18-HP-WMAH-230D25-O wall-mounted air handler, a 25 ft QuickConnect® pre-charged line set, and the required DIYPRO® cable.
Built for extreme winter performance, this MRCOOL Hyper Heat system provides dependable heating operation down to -22°F while also delivering efficient cooling for spaces up to 800 sq. ft. It is ideal for garages, bonus rooms, bedrooms, basements, offices, cabins, workshops, detached buildings, and other spaces where standard mini splits may struggle in colder weather.
Unlike traditional ductless mini split systems, the MRCOOL DIY series uses factory-sealed No-Vac® QuickConnect® pre-charged line sets filled with R-454B refrigerant. That means no vacuum pump, no gauges, no nitrogen purge, no refrigerant charging, and no HVAC certification required for the line set connection. Because apparently HVAC finally decided homeowners deserve one system that does not require a tool cart the size of a small moon.
What's Included in This Complete DIY Bundle?
- DIYHH-18-HP-C-230D25-O – 18K Hyper Heat Outdoor Condenser, 208/230V
- DIY-18-HP-WMAH-230D25-O – 18K Wall-Mounted Air Handler
- DIY25-1412 – 25 ft Pre-Charged QuickConnect® Line Set
- DIYPRO® Cable
- Wireless Remote
- Installation Manuals
- Mounting Hardware
Why Choose the MRCOOL DIYHH-18 Hyper Heat?
- True cold-climate Hyper Heat performance down to -22°F
- 18,000 BTU heating and cooling capacity
- Designed for spaces up to 800 sq. ft.
- DIY-friendly No-Vac® QuickConnect® installation
- No vacuum pump, gauges, nitrogen, or refrigerant handling required
- Factory pre-charged R-454B refrigerant line set included
- Efficient inverter rotary compressor technology
- Up to 21.2 SEER2 efficiency
- Built-in smart control with MRCOOL SmartHVAC App
- Compatible with Amazon Alexa® and Google Assistant®
- Quiet indoor operation as low as 19 dBA
- Excellent choice for garages, cabins, additions, shops, and cold-climate homes
Ideal Applications
- Garage mini split heating and cooling
- Detached shop or workshop HVAC
- Basements and finished lower levels
- Bonus rooms and room additions
- Cabins and mountain homes
- Master bedrooms and large bedrooms
- Home offices and studios
- Home gyms
- Airbnb and rental properties
- Barndominiums and pole barns
- Small commercial offices or retail spaces
Line Set Length Information
This system includes a standard 25 ft QuickConnect® pre-charged line set. Extended line set options may add an additional line set, couplers, and a longer control wire for installations requiring more distance between the indoor air handler and outdoor condenser.
Always verify the required line set length before ordering. Excess line set should not be cut. It should be properly coiled and installed according to MRCOOL installation guidelines.
Condenser Performance Specifications
| Specification | Value |
|---|---|
| Outdoor Model | DIYHH-18-HP-C-230D25-O |
| System Type | Single-Zone Hyper Heat Mini Split |
| BTU Rating | 18,000 BTU Heating & Cooling |
| Recommended Coverage Area | Up to 800 sq. ft. |
| SEER2 | 21.2 |
| EER2 | 12.5 |
| HSPF2-4 | 11 |
| HSPF2-5 | 8.5 |
| Minimum Heating Ambient Temperature | -22°F |
| Operating Temperature Range | -22°F to 122°F |
| Compressor Type | Inverter Rotary |
| Airflow | 1765.8 CFM |
| Condenser Noise Level | 58 dBA |
Condenser Electrical Specifications
| Electrical Specification | Value |
|---|---|
| Voltage | 208/230V |
| Phase | 1 Phase |
| Cycle | 60Hz |
| Minimum Circuit Ampacity | 19A |
| Maximum Fuse / Breaker | 25A |
| Dedicated Circuit Required | Yes |
Refrigeration & Line Set Specifications
| Refrigeration Specification | Value |
|---|---|
| Refrigerant | R-454B |
| Factory Charge Volume | 52.21 oz |
| Included Line Set | 25 ft Pre-Charged QuickConnect® Line Set |
| Maximum Supported Line Length | 75 ft |
| Liquid Line Size | 1/4 in. |
| Suction Line Size | 1/2 in. |
| Metering Device | Electronic Expansion Valve, EEV |
| Vacuum Pump Required | No |
| Field Refrigerant Charging Required | No |
Condenser Dimensions & Weight
| Dimension | Value |
|---|---|
| Net Dimensions | 35.04 in. W × 26.5 in. H × 13.46 in. D |
| Net Weight | 99.87 lbs |
| Gross Dimensions | 40.55 in. W × 29.53 in. H × 18.11 in. D |
| Gross Weight | 120.15 lbs |
Wall Mount Air Handler Specifications
| Indoor Unit Specification | Value |
|---|---|
| Indoor Model | DIY-18-HP-WMAH-230D25-O |
| Indoor Unit Type | Wall-Mounted Air Handler |
| BTU Capacity | 18,000 BTU |
| Coverage Area | Up to 800 sq. ft. |
| Fan Speeds | 5-Speed |
| Quiet Mode | Yes |
| Noise Level | 19 dBA Low – 54.5 dBA High |
| Net Dimensions | 42.52 in. W × 13.19 in. H × 8.9 in. D |
| Net Weight | 35.49 lbs |
| Gross Dimensions | 46.73 in. W × 14.29 in. H × 17.68 in. D |
| Gross Weight | 49.6 lbs |
Smart Control Features
| Smart Feature | Included |
|---|---|
| MRCOOL SmartHVAC App | Yes |
| iOS Compatible | Yes |
| Android Compatible | Yes |
| Amazon Alexa® Voice Control | Yes |
| Google Assistant® Voice Control | Yes |
| Wireless Remote Included | Yes |
Warranty Coverage
| Warranty Item | Coverage |
|---|---|
| Compressor Warranty | 7-Year Compressor Warranty with Registration |
| Parts Warranty | 5-Year Parts Warranty with Registration |
| Extended Warranty | Extended Limited Lifetime Coverage Available with MRCOOL Care Registration |
Hyper Heat vs Standard DIY Mini Splits
Standard DIY mini split systems are excellent for mild and moderate climates, but they may lose heating output as outdoor temperatures drop. The MRCOOL DIYHH-18 Hyper Heat system is designed for colder regions where winter heating performance matters.
With true low-temperature operation down to -22°F, this system is a better choice for homeowners who need dependable heat in garages, cabins, workshops, basements, additions, and cold-climate living spaces.
Frequently Asked Questions
Can I install the MRCOOL DIYHH-18 myself?
Yes. This system is designed for DIY installation using MRCOOL No-Vac® QuickConnect® pre-charged line set technology. No vacuum pump, gauges, nitrogen purge, or refrigerant charging are required for the line set connection.
Does this system require a dedicated electrical circuit?
Yes. The outdoor condenser requires a dedicated 208/230V electrical circuit with a minimum circuit ampacity of 19A and a maximum fuse or breaker size of 25A.
Will this system heat when it is below freezing?
Yes. The MRCOOL DIYHH-18 Hyper Heat system is engineered for heating operation down to -22°F, making it a strong choice for cold-climate installations.
Do I need to buy refrigerant separately?
No. The included QuickConnect® line set is pre-charged, and the system is designed for installation without field refrigerant charging.
What size space will this 18K Hyper Heat mini split cover?
This 18,000 BTU system is rated for spaces up to approximately 800 sq. ft. Actual sizing depends on insulation, ceiling height, sun exposure, layout, climate zone, and other building conditions.
Is this a good option for a garage or workshop?
Yes. The MRCOOL DIYHH-18 Hyper Heat is an excellent choice for garages, workshops, detached buildings, and other spaces that need both efficient cooling and strong cold-weather heating.
Can I control this system from my phone?
Yes. This system works with the MRCOOL SmartHVAC App and is compatible with iOS, Android, Amazon Alexa®, and Google Assistant®.
Why Buy From MRCOOL DIY Direct?
MRCOOL DIY Direct specializes in MRCOOL DIY systems, parts, bundles, and support. Our team understands these systems and can help verify sizing, electrical requirements, line set selection, and system compatibility before you order.
You are not buying from a random dropshipper copying model numbers into a spreadsheet and hoping the freight truck solves the rest. You are buying from a dedicated MRCOOL dealer focused on helping customers get the correct system the first time.
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy