Free curbside shipping on eligible MRCOOL® systems across the continental U.S. Most products ship in 3–5 business days and arrive in 4–10 days, depending on your location. Freight carriers will call to schedule delivery.
Returns accepted within 30 days on new, unopened items in original packaging. A restocking fee of up to 35% may apply for HVAC equipment — we’ll always confirm before issuing a return authorization.
Each MRCOOL® system is backed by manufacturer warranty coverage as defined by product and model — typically 5–10 years on major components. Register your system after installation to activate full coverage.
Need help with sizing, voltage or compatibility? Email support@coolheatdirect.com — our U.S. team replies within one business day.
MODEL: DIYHH-12-HP-WM-230D25-O
Built for Winter.
Extreme Cold Heating. Powerful Cooling. DIY Simple.
Still worried your home won't stay warm when temperatures plunge?
The MRCOOL® DIY® Hyper Heat 12K BTU Mini Split System was built for homeowners who refuse to let winter dictate their comfort. While many heating systems struggle in extreme cold, Hyper Heat technology continues delivering reliable heating in temperatures as low as -22°F, helping keep your space warm, comfortable, and energy efficient when you need it most.
Perfect for bedrooms, home offices, cabins, guest rooms, workshops, and other spaces up to 550 sq ft, this system combines exceptional cold-weather performance with the installation simplicity that made MRCOOL® DIY® a homeowner favorite. The included 25 ft QuickConnect® line set comes pre-charged with R-454B refrigerant, helping simplify installation without specialized HVAC tools.
Advanced DC inverter technology, industry-leading 23.5 SEER2 efficiency, SmartHVAC® app control, Amazon Alexa®, Google Assistant®, and the included DIYPRO® cable give you complete control, outstanding efficiency, and dependable comfort in every season.
Whether it's a freezing winter morning or the hottest day of summer, Hyper Heat delivers the confidence of knowing your comfort system is ready.
Warm when others struggle. Cool when others quit. Built for extreme climates.
Why You'll Love It
✅ Reliable heating in temperatures as low as -22°F
✅ Ideal for spaces up to 550 sq ft
✅ Exceptional 23.5 SEER2 energy efficiency
✅ Simplified DIY installation with QuickConnect® technology
✅ SmartHVAC® app control from anywhere
✅ Compatible with Amazon Alexa® & Google Assistant®
✅ Gold Fin® corrosion-resistant condenser protection
✅ Includes 25 ft pre-charged QuickConnect® line set
Best For
Bedrooms • Home Offices • Guest Rooms • Cabins • Sunrooms • Small Living Areas • Workshops • Cold Climate Homes
What's Included
1 × MRCOOL® DIY® Hyper Heat 12K BTU Condenser
1 × MRCOOL® DIY® 12K BTU Wall-Mounted Air Handler
1 × 25 ft QuickConnect® Line Set (1/4" × 3/8")
1 × MRCOOL® Remote Control
1 × DIYPRO® Cable
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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