The MRCOOL DIY 5th Gen 18K BTU 22.5 SEER2 Ductless Mini Split Heat Pump is a single-zone system that heats and cools one room up to 800 square feet.
This wall mount unit offers easy do-it-yourself installation with no special tools or professional services needed. Your order ships with a pre-charged 25-foot DIY QuickConnect line set and pre-charged with R-454B refrigerant.
The MRCOOL Gold Fin Condenser provides corrosion resistance coating designed to protect the condenser coils from outside environmental damage.
Ideal for
- Open living rooms and great rooms
- Large bedrooms
- Home offices
- Garages and detached workshops
Best for: homeowners looking for a DIY-friendly installation for a single-zone mini-split for heating and cooling for one room
Features
- 22.5 SEER2 efficiency. ENERGY STAR certified inverter operation that ramps up and down instead of cycling on and off, which is what keeps power bills down.
- Barely a whisper indoors. The air handler runs as low as 19 dBA, quieter than rustling leaves.
- Control from anywhere. Included remote, SmartHVAC app on your phone, or just ask Alexa or Google Assistant.
- Follow Me comfort. The remote senses the temperature where you're sitting, not at the wall, so the room feels the way you set it.
- Built to last outside. Gold Fin coating on the condenser resists corrosion from rain, salt air, and the elements.
- Washable filter plus Dry, Quiet, Sleep, and Fan Only modes for year-round comfort with no recurring filter cost.
Key Specs
- 18,000 BTU (1.5 ton) heating and cooling
- 22.5 SEER2, 13.7 EER2, 11.5 HSPF2
- Covers up to 800 sq ft
- 208/230V, 20A max breaker
- Air handler: 19 to 54.5 dBA, 42.5" W x 13.2" H x 8.9" D
- Condenser: 35" W x 26.5" H x 13.5" D, 93.5 lbs
- 25 ft pre-charged R-454B DIY® Quick Connect line set, extendable to 98.4 ft
- Wi-Fi, iOS and Android app, Alexa and Google Assistant
- ENERGY STAR, AHRI certified, UL and ETL listed
What's Included
-
1 x MRCOOL DIY 18K BTU 5th Gen Ductless Mini Split Condenser - 230V, DIY-18-HP-C-230D25-O -
1 x MRCOOL DIY 18K BTU 5th Generation Wall Mount Air Handler - 230V, DIY-18-HP-WMAH-230D25-O -
1 x MRCOOL DIY 5th Gen Pre-Charged R-454B Quick Connect Line Set - 25 ft
What you should know
This is a complete single-zone system, so nothing else is required to run it except a dedicated 208/230V circuit. The included 25-foot line set covers the majority of installation. Includes a wall mounting template and DIY PRO Cable that eliminates the need for traditional electrical conduit while protecting the wiring from weather and outdoor hazards.
Warranty
- 7-year compressor coverage
- 5-year parts coverage
Specifications:
BRAND NAME |
MRCOOL |
SERIES |
DIY 5th gen Single-Zone Mini-splits |
CONDENSER MODEL |
DIY-18-HP-C-230D25-O |
AIR HANDLER MODEL |
DIY-18-HP-WMAH-230D25-O |
CONDENSER GTIN |
840255586962 |
AIR HANDLER GTIN |
840255587044 |
SEER2 |
22.5 |
EER2 |
13.7 |
HSPF2-4 |
11.5 |
HSPF2-5 |
8.5 |
TONNAGE |
1.5 |
COOLING CAPACITY (BTU) |
18,000 |
HEATING CAPACITY (BTU) |
18,000 |
VOLTAGE (V) |
208/230 |
PHASE |
1 |
CYCLE |
60 |
MAX FUSE BREAKER (A) |
20 |
MIN CIRCUIT AMPACITY (A) |
18 |
COLOR |
White |
ZONE CAPACITY |
1 |
REFRIGERANT TYPE |
R-454B |
REFRIGERANT VOLUME (OZ) |
44.8 |
DECIBEL RATING (DBA) |
58.5 |
INVERTER |
DC |
LINE SET LENGTH |
25 ft |
MAX LINESET LENGTH (FT) |
98.4 ft |
LIQUID LINE SIZE |
1/4 in |
SUCTION LINE SIZE |
1/2 in |
COMPRESSOR MOTOR TYPE |
Rotary |
AUXILIARY HEATER INCLUDED |
No |
AUXILIARY HEATER AVAILABLE |
No |
FAN ONLY OPTION |
Yes |
QUIET MODE |
Yes |
AUTO COOL |
Yes |
WIFI COMPATIBILITY |
Yes |
APP COMPATIBILITY |
Yes |
WORKS WITH IOS |
Yes |
WORKS WITH ANDROID |
Yes |
UL LISTED |
Yes |
ETL LISTED |
Yes |
ENERGY STAR CERTIFIED |
Yes |
AHRI CERTIFIED |
Yes |
MOUNT TYPE |
Wall |
MAX COVERAGE AREA |
800 sqft |
DECIBEL RATING LOW (DBA) |
19 |
DECIBEL RATING HIGH (DBA) |
54.5 |
OSCILLATION |
Yes |
FILTER TYPE |
Reusable |
REMOTE CONTROL INCLUDED |
Yes |
BASE PARTS WARRANTY |
5 years |
BASE COMPRESSOR WARRANTY |
7 years |
REGISTERED WARRANTY |
Extended Limited Lifetime |
CONDENSER NET DIMENSIONS (D X H X W) |
13.46 x 26.5 x 35.04 in |
CONDENSER NET WEIGHT |
93.48 lb |
CONDENSER GROSS DIMENSIONS (D X H X W) |
18.11 x 29.53 x 40.55 in |
CONDENSER GROSS WEIGHT |
114.2 lb |
AIR HANDLER NET DIMENSIONS (D X H X W) |
8.9 x 13.19 x 42.52 in |
AIR HANDLER NET WEIGHT |
35.49 lb |
AIR HANDLER GROSS DIMENSIONS (D X H X W) |
17.68 x 14.29 x 46.73 in |
AIR HANDLER GROSS WEIGHT |
49.6 lb |
Need help?
Call us at 1-800-514-2418 and our HVAC product specialists will help answer your questions and customize your MRCOOL DIY 18K BTU 22.5 SEER2 5th Gen Heat Pump System.
Order online in minutes. Secure checkout, free shipping, and no sales tax.

Good AirX is an Authorized MRCOOL Dealer. Every unit ships new, factory-sealed, and fully covered by MRCOOL's manufacturer warranty.
Frequently Asked Questions
Here are some of the most asked questions about MRCOOL DIY 18K BTU 5th Gen Heat Pump System setup.
What room size is this 18,000 BTU unit for?
This unit is designed to cool and heat a large room or open space measuring up to 800 square feet. Ideal for large open rooms, master bedrooms, home offices or garages.
Is this a complete system or only the indoor unit?
Yes, the MRCOOL DIY 18K BTU 22.5 SEER2 5th Gen Ductless Mini Split Heat Pump System - 230V is a complete system that includes both the indoor air handler and the outdoor condenser unit.
Can I really install this myself? What tools do I need?
Yes, you can install the MRCOOL DIY 5th Gen 18K BTU Mini-Split System yourself without specialized HVAC tools or a professional technician, thanks to its patented pre-charged QuickConnect line sets. Most homeowners can have this unit successfully installed in a day or two, with many often taking just a few hours.
How long is the included line set? Can I get a longer one?
This system includes a 25-foot pre-charged line set. You can also order a longer line set. MRCOOL offers pre-charged line set lengths from 16 to 75 feet for their DIY mini-split systems.
Does it heat as well as it cools? What are the temperatures?
Yes. You get 18,000 BTU of heat, the same as the cooling. It heats down to -13°F and cools up to 122°F.
What warranty do I get if I install it myself?
MRCOOL offers a 5-year parts warranty and a 7-year compressor warranty. The 5-year parts coverage includes the electrical components, circuit boards, fan motors and coils in both the indoor and outdoor units. Installing it yourself does not void the warranty as long as you follow the installation instructions.
What is included in the box?
MRCOOL DIY 18K BTU 5th Gen Ductless Mini Split Heat Pump System (230V) includes:
- 18,000 BTU Wall-Mounted Air Handler (Indoor Unit)
- Outdoor Condenser with Gold Fin corrosion resistance (Outdoor Unit)
- 25-ft. Pre-Charged Quick-Connect Line Set (pre-filled with R-454B refrigerant)
- DIY PRO Cable (replaces traditional electrical conduit for weather and yardwork protection)
- Wireless Remote Control (with batteries)
- MRCOOL Smart HVAC Wi-Fi Module (for app control and smart home integration via Alexa/Google Assistant)
- Installation Accessories (including wall mounting plate, cardboard mounting/marking template, wall penetration insulation/foam, and mounting screws)
- Manuals and Documentation
What is your return policy?
We offer a 30 day returns for completely unused, uninstalled and in their original factory packaging in resalable condition units with restocking fees. Pre-charged line sets are non-returnable. Learn more about our Refund Policy.
Do you offer free shipping and where do you deliver to?
We offer free shipping and no sales tax on all of our MRCOOL products in the contiguous United States. We do not ship to Alaska, Hawaii, Canada, Puerto Rico or the Caribbean.
How is my unit shipped and delivered?
Your MRCOOL unit will be shipped from the manufacturer via LTL (Less-Than-Truckload) freight carrier on a pallet. We offer standard curbside delivery with a semi-truck with a liftgate delivery on the pallet to your shipping address. The driver will not move the boxes inside your home or garage. Please inspect your order for any damage before accepting and signing for the delivery.










