MRCOOL® DIY 18K Hyper Heat 5th Gen Mini Split System
Summary
The MRCOOL® DIYHH-18 Hyper Heat 18K Mini Split System is a 2025 5th Generation innovation engineered for true cold-climate performance down to -22°F with genuine DIY installation. This complete bundle delivers powerful 18,000 BTU heating and cooling for spaces up to 800 sq. ft., combining professional HVAC capability with homeowner-friendly setup.
Featuring the advanced DIYHH-18-HP-C-230D25-O outdoor condenser and DIY-18-HP-WMAH-230D25-O wall-mounted air handler, this system utilizes factory-sealed QuickConnect® pre-charged line sets with R-454B refrigerant—eliminating the need for vacuum pumps, gauges, or HVAC certification. With high efficiency ratings of 21.2 SEER2 and 11 HSPF2-4, smart controls via the MRCOOL SmartHVAC App, and compatibility with Alexa and Google Assistant, this system offers premium, reliable comfort for garages, additions, workshops, and whole-room applications.
What's Included
- Outdoor Condenser (MRCOOL® DIYHH-18 Hyper Heat Condenser - DIYHH-18-HP-C-230D25-O)
- Wall-Mounted Air Handler (MRCOOL® DIY-18 Wall Mount Air Handler - DIY-18-HP-WMAH-230D25-O)
- 25 ft Pre-Charged QuickConnect® Line Set (DIY25-1412)
- DIYPRO® Communication Cable
- Wireless Remote Control
- Complete Mounting Hardware & Template
- Installation and User Manuals
Warranty
- 7-Year Compressor Warranty (Registration Required)
- 5-Year Parts Warranty (Registration Required)
- Extended Limited Lifetime Coverage with MRCOOL® Care
Important: Warranty benefits require product registration. Refer to MRCOOL's official warranty documentation for full terms and conditions.
Technical Information
Model Number: DIYHH-18-HP-C-230D25-O (MRCOOL® DIYHH-18 Hyper Heat Outdoor Condenser)
|
BRAND NAME |
MRCOOL |
|
SERIES |
DIY Hyper Heat 5th Gen |
|
MODEL |
DIYHH-18-HP-C-230D25-O |
|
UNIT TYPE |
Mini-Split |
|
EQUIPMENT TYPE |
Condenser |
|
SHORT DESCRIPTION |
18K Hyper Heat 230V Condenser with QuickConnect® |
|
COOLING CAPACITY (BTU) |
18,000 |
|
HEATING CAPACITY (BTU) |
18,000 |
|
SEER2 |
21.2 |
|
EER2 |
12.5 |
|
HSPF2-4 |
11 |
|
HSPF2-5 |
8.5 |
|
VOLTAGE (V) |
208/230 |
|
PHASE |
1 |
|
CYCLE |
60 Hz |
|
MIN CIRCUIT AMPACITY (A) |
19 |
|
MAX FUSE BREAKER (A) |
25 |
|
MIN AMBIENT HEAT (F) |
-22°F |
|
MAX AMBIENT COOL (F) |
122°F |
|
CFM |
1765.8 |
|
COMPRESSOR TYPE |
Inverter Rotary |
|
REFRIGERANT TYPE |
R-454B |
|
REFRIGERANT VOLUME (OZ) |
52.21 oz |
|
METERING DEVICE |
Electronic Expansion Valve (EEV) |
|
LINE SET INCLUDED |
Yes |
|
LINE SET LENGTH |
25 ft |
|
MAX LINESET LENGTH (FT) |
75 ft |
|
LIQUID LINE SIZE |
1/4" |
|
SUCTION LINE SIZE |
1/2" |
|
DECIBEL RATING HIGH (DBA) |
58 |
|
NET WIDTH (IN) |
35.04 |
|
NET HEIGHT (IN) |
26.5 |
|
NET DEPTH (IN) |
13.46 |
|
NET WEIGHT (LBS) |
99.87 |
Model Number: DIY-18-HP-WMAH-230D25-O (MRCOOL® DIY-18 Wall-Mount Air Handler)
|
BRAND NAME |
MRCOOL |
|
SERIES |
DIY 5th Gen |
|
MODEL |
DIY-18-HP-WMAH-230D25-O |
|
UNIT TYPE |
Mini-Split |
|
EQUIPMENT TYPE |
Air Handler |
|
SHORT DESCRIPTION |
18K 230V Wall Mount Air Handler |
|
COOLING CAPACITY (BTU) |
18,000 |
|
HEATING CAPACITY (BTU) |
18,000 |
|
MAX COVERAGE AREA |
800 sq. ft. |
|
MOUNT TYPE |
Wall |
|
FAN SPEEDS |
5-Speed |
|
QUIET MODE |
Yes |
|
DECIBEL RATING LOW (DBA) |
19 |
|
DECIBEL RATING HIGH (DBA) |
54.5 |
|
NET WIDTH (IN) |
42.52 |
|
NET HEIGHT (IN) |
13.19 |
|
NET DEPTH (IN) |
8.9 |
|
NET WEIGHT (LBS) |
35.49 |
|
SMART FEATURES |
MRCOOL SmartHVAC App, Alexa, Google Assistant, Wireless Remote |
System Highlights
- 2025 5th Generation Hyper Heat: Newest model with enhanced cold-climate performance down to -22°F.
- True DIY Installation: Pre-charged QuickConnect® line set requires no special HVAC tools or certification.
- High-Capacity 18K BTU: Ideal for spaces up to 800 sq. ft. including large rooms, garages, and workshops.
- Premium Efficiency: 21.2 SEER2 and 11 HSPF2-4 ratings for superior energy savings.
- Smart Connectivity: Full control via MRCOOL SmartHVAC App, voice commands (Alexa/Google Assistant), and included remote.
- Quiet Operation: Indoor unit operates as low as 19 dB for undisturbed comfort.
- Complete Bundle: Everything included for a single-zone installation—just add electrical connection.
- Robust Warranty: Industry-leading 7-year compressor and 5-year parts warranty with registration.
Frequently Asked Questions
Q: Is this system really DIY-friendly?
A: Yes. The pre-charged, factory-sealed QuickConnect® line set eliminates the most complex steps of traditional mini-split installation. No vacuum pump, gauges, or refrigerant handling is required.
Q: How low of a temperature can it heat?
A: This Hyper Heat system is engineered to provide effective heating down to -22°F outdoor temperature.
Q: What electrical requirements are needed?
A: A dedicated 208/230V circuit with a 25A breaker is required (19A minimum circuit ampacity).
Q: Is the line set included?
A: Yes, a 25-foot pre-charged QuickConnect® line set is included. Extended lengths are available as options.
Q: Does it come with smart controls?
A: Yes. The system includes WiFi capability for the MRCOOL SmartHVAC App and is compatible with Amazon Alexa and Google Assistant for voice control.
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We will prepare your order within 24 hours if it’s received on a weekday (before noon). Orders are shipped in one to two business days. Transit time is between 3 to 6 business days, although exceptions apply. We email tracking information once your purchase is shipped.
Delivery Map

IMPORTANT DELIVERY INFORMATION: Please be kindly informed that this air conditioner, due to its weight and shipping restrictions, is shipped palletized with an arranged freight service and requires an appointment for delivery. To AVOID delays, please check if the provided phone number in the order details is a current number where you can be reached. You can also contact the carrier directly and refer to your tracking number to set up a date and time for your appointment. It is your responsibility to ensure a safe and secure environment for delivery. Please note that we cannot be held liable for any packages that are stolen or lost after delivery has been confirmed. PLEASE verify your shipping address, as changes to the address after freight has shipped can result in an additional 15% or higher fee depending on freight weight and dimensions.
SMALLWARES INFORMATION: Please be informed that for smaller items, such as Installation Kits, Smart Connectivity Dongles, and TTW Sleeves, when these items are ordered individually, they may be shipped via FedEx without a signature requirement. It is your responsibility to ensure a safe and secure environment for delivery. Please note that we cannot be held liable for any packages that are stolen or lost after delivery has been confirmed. Thank you for your understanding and cooperation.
INSPECT YOUR MERCHANDISE BEFORE SIGNING: Please inspect your boxes thoroughly when you receive them. They should arrive shrink-wrapped and on a pallet. If you notice any damages or imperfections (e.g. crushed box or forklift hole), please write comments on the receipt before signing for delivery, no matter how small damages seem. Contact us immediately to assist you.
Shipping & Delivery
We will prepare your order within 24–48 hours if it’s received on a weekday (before noon). Orders are shipped in one to two business days. Transit time is between 3 to 6 business days, although exceptions apply. We email tracking information once your purchase is shipped.
Delivery Map
IMPORTANT DELIVERY INFORMATION
Please be informed that this air conditioner, due to its weight and shipping restrictions, is shipped palletized with an arranged freight service and requires an appointment for delivery.
To AVOID delays, please make sure the phone number in your order details is accurate and one where you can be reached. You may also contact the carrier directly using your tracking number to schedule your delivery.
It is your responsibility to ensure a safe and secure delivery environment. We are not liable for any packages that are stolen or lost after delivery is confirmed.
Please verify your shipping address carefully. Changes to your shipping address after the freight has been shipped may result in additional fees of 15% or more, depending on freight weight and dimensions.
SMALLWARES INFORMATION
Smaller items such as Installation Kits, Smart Connectivity Dongles, and TTW Sleeves may be shipped via FedEx without a signature requirement if ordered individually.
It is your responsibility to ensure a safe delivery location. We are not liable for packages lost or stolen after delivery confirmation. Thank you for your understanding and cooperation.
INSPECT YOUR MERCHANDISE BEFORE SIGNING
Please inspect your boxes carefully upon delivery. Shipments should arrive shrink-wrapped and on a pallet. If you notice any damage or signs of mishandling (such as a crushed box or forklift puncture), write comments on the delivery receipt before signing, even if the damage appears minor.
Contact us immediately if any issues arise so we can assist you promptly.
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