MRCOOL® 5th Gen 18K BTU Hyper Heat DIY Condenser (R-454B Heats to –22°F QuickConnect) — DIYHH-18-HP-C-230D25-O

Product Description 

Introducing what’s  New 2025 MRCOOL® DIYHH-18-HP-C-230D25-O — 5th Gen 18K BTU Hyper Heat DIY Condenser (R-454B | Heats to –22°F | QuickConnect)

Short Description 

Introducing what’s  New 2025 The MRCOOL® DIYHH-18-HP-C-230D25-O is the strongest 18K BTU Hyper Heat DIY condenser on the market, engineered for powerful year-round comfort and reliable heating down to –22°F. With a factory-charged R-454B QuickConnect® line set, this system installs without vacuum pumps, gauges, EPA licenses, or refrigerant handling—delivering professional-grade performance with true DIY simplicity.

 

FULL PRODUCT DESCRIPTION

The 5th Gen DIY Mini Split That Leaves Others Behind

If you want the best 18,000 BTU DIY mini split for cold climates, you’re looking at it.

The MRCOOL DIYHH-18 Hyper Heat condenser is built on MRCOOL’s 5th Generation platform, delivering:

• Stronger heat output
• Higher efficiency
• Lower refrigerant environmental impact
• More durable outdoor performance
• Cleaner, quieter inverter operation

No refrigerant handling.

No vacuum pump.

No licensed HVAC installer.

Just connect, tighten, and turn it on.

This system is why MRCOOL dominates the DIY market.

Hyper Heat Performance

Most “DIY mini splits” start dying below 15°F.

This one keeps heating normally at –22°F.

That makes it unstoppable in:

• Midwest winters
• Tennessee/Kentucky cold snaps
• Mountain & northern states
• Coastal harsh climates

No one  will not find this capability on cheap brands or 4th Gen units.

 Smarter, Quieter, More Efficient

The 5th Gen inverter controls compressor output to maintain steady living conditions without loud cycling or temperature swings.

The result:

• Lower energy bills
• Longer component life
• Premium comfort you can actually feel

This is the gold standard DIY system for garages, bedrooms, barndominiums, offices, rental units, tiny homes, or any space where ductwork is a nightmare.

 What’s Included 

✔ MRCOOL DIYHH-18-HP-C-230D25-O Hyper Heat Condenser

✔ 25 ft pre-charged R-454B QuickConnect® line set (DIY25-1412)

✔ Installation hardware

No vacuuming or refrigerant tools required.

✔ Compatible Indoor Units

• DIY-18-HP-WMAH-230D25-O Wall Mount Air Handler
• DIYCASSETTE18HP-230D25-O OuttaSight® Ceiling Cassette

Both connect instantly using QuickConnect® sealed fittings.

Perfect for:

• Master bedrooms
• Home offices
• Garages and workshops
• Barndominiums
• Tiny homes
• ADUs and apartments
• Old homes with no ductwork
• Bonus rooms above garages
• New builds where mini splits shine

If you can operate a drill, you can install this condenser.

 Warranty That Crushes Every Other DIY claimed Brand

MRCOOL stands behind their 5th Gen systems:

• 7-Year Compressor Warranty
• 5-Year Parts Warranty
• Eligible for Limited Lifetime Replacement with MRCOOL® Care

If the compressor fails inside warranty — they replace it. 

No “repair only” BS like you get from other brands.

 Feature Highlights

• Hyper Heat down to –22°F
• 21.2 SEER2 high efficiency
• 11 HSPF2 heating
• Energy Star® certified
• R-454B next-gen refrigerant (way lower GWP than R-410A)
• 25 ft pre-charged QuickConnect® line set
• DIYPRO® cable protects electrical from pests & weather (comes with indoor unit)
• Gold Fin® anti-corrosion coating
• SmartHVAC™ App + Alexa + Google Assistant integration
• Quiet outdoor operation
• Auto restart, timer, anti-mildew features

 MRCOOL vs Other DIY Brands 

Pioneer, Gree, Mitsubishi, and Amazon clone units require vacuum pumps, gauges, and refrigerant charging.

The DIYHH-18 does not.

You get:

• Factory-charged lines
• Closed refrigeration circuit
• No EPA license
• No chemical exposure
• No installer cost

Install in 2–4 hours and enjoy professional performance.

Specifications 

BTU: 18,000

Coverage: 500–800 sq ft

Voltage: 208/230V

MAX FUSE BREAKER (A)  25 double pole 

MIN CIRCUIT AMPACITY (A) 19 double pole 

SEER2: 21.2

HSPF2: 11 / 8.5

Compressor: Rotary Inverter

Refrigerant: R-454B

Noise: 58 dBA

Line Set Included: 25 ft QuickConnect®

Max Lineset: 75 ft

Liquid Line: 1/4”

Suction Line: 1/2”

Metering: EEV

Energy Star: Yes

AHRI Certified: Yes

Weight: 99.87 lbs

Dimensions:

W: 35.04” • H: 26.50” • D: 13.46”

FAQ asked questions 

Does it really work in cold weather?

Yes. Hyper Heat models deliver full-capacity heating down to –22°F.

Can I install it myself?

Yes.

QuickConnect® line sets arrive pre-charged, sealed, and vacuumed from the factory.

No gauges.

No refrigerant handling.

No HVAC license.

You only need a licensed electrician to connect 230V safely.

 What size space does 18K BTU cover?

500–800 sq ft, depending on:

• Ceiling height
• Sun exposure
• Insulation
• Door & window count

 Is it Wi-Fi compatible?

Yes.

Control with:

• SmartHVAC™ App
• Alexa
• Google Assistant
• Included remote

Why Buy Direct 

We are the USA’s #1 trusted MRCOOL dealer.Every unit ships factory sealed, brand new, full manufacturer warranty, and eligible for extended protection.

Better pricing: No middleman markup. 

Faster support: Talk to real MRCOOL experts.

Confidence: Buy direct — stay protected.

 

 Notes & Disclaimers

Specifications may update during production.Images may reflect representative components.Verify indoor unit configuration before ordering