🧰 Why Homeowners Love DIY MRCOOL Systems
The MRCOOL DIY Mini Split Series was designed with the hands-on homeowner in mind. The 27,000 BTU 2-zone model (typically paired with 9k + 12k air handlers) is one of the largest DIY-capable units available, making it ideal for medium-size homes or dual-zone spaces like a living room and bedroom.
What makes it DIY-friendly?
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Pre-charged line sets — no need to handle refrigerant
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Quick-connect fittings — simple, tool-free hookup
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Step-by-step guides & videos — from MRCOOL and resellers
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Modular zoning — install one air handler at a time
🛒 Tools You’ll Need (and What You Don’t)
✅ Required Tools
| Tool | Use |
|---|---|
| Cordless drill/driver | For mounting brackets and wall anchors |
| Stud finder | To locate safe mounting areas |
| Level | Ensures air handlers and brackets are aligned |
| Hole saw (3.5” or 4”) | To create the line set passthrough |
| Utility knife | For trimming insulation and sealing materials |
| Torque wrench | Tightening flare nuts to spec (optional but recommended) |
❌ Not Required
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HVAC vacuum pump
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Refrigerant gauge
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EPA 608 certification
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Brazing torch
That’s what makes this kit DIY-compliant—it’s sealed and charged from the factory.
🕒 How Long Will It Take?
🏠 For Most Homeowners:
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Prepping tools and space: 1–2 hours
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Mounting and installing each air handler: 1.5–2.5 hours per zone
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Running line sets & electrical wiring: 3–6 hours total
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Final connections & testing: 1 hour
💡 Estimated Total Time: 8–12 hours (1–2 days)
You can break it into chunks—one air handler on Saturday, one on Sunday.
👷♂️ What’s the Required Skill Level?
You don’t need to be an HVAC tech, but you should be comfortable with power tools, drilling through walls, and basic electrical work.
Recommended experience:
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Installed a ceiling fan or light fixture
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Mounted a TV or wall shelf
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Used a hole saw or drill driver safely
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Familiar with turning off breaker panels
If you’re not sure about the electrical hookup (220V), an electrician can handle just that part in under an hour.
⚠️ Always turn off the circuit breaker before working with high-voltage connections.
🧱 What Type of Wall Do You Need?
You’ll drill a 3.5"–4" hole through an exterior wall behind each indoor air handler. Suitable wall types include:
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Wood frame with drywall interior & siding/exterior
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Brick veneer (may need special masonry bit)
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Concrete block (more advanced tools required)
Wall sleeves and covers are included to protect the line set penetration.
🔌 Electrical Requirements: Read Before You Start
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Voltage: 208/230V
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Amperage: Typically 30 amps
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Breaker type: Dedicated double-pole breaker
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Wiring: 10/2 or 12/2 (consult your manual or electrician)
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Disconnect box: Required per NEC code
Most homeowners will hire an electrician for the breaker hookup, even if they install the air handlers themselves.
🪟 Line Set Routing: What to Expect
The 27k system comes with two pre-charged line sets (often 25 ft each). You’ll need to:
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Run them outside via the wall sleeve
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Connect to the condenser using included Quick Connect valves
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Wrap excess line neatly or use an optional line set cover kit
You can purchase 16', 25', 35', or 50' sets if longer runs are needed. Just match the BTU capacity per zone.
🛑 When Should You NOT DIY?
While MRCOOL’s 5th Gen DIY systems are simple to install, DIY may not be right for everyone. Consider hiring a pro if:
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You're uncomfortable drilling through exterior walls
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You don’t understand 220V electrical safety
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You need to run conduit through a crawlspace or attic
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You live in a city with strict permit or inspection rules
✅ Pro Tip: You can do the mounting and leave only the power hookup to a licensed electrician for a hybrid install.
✅ Final Installation Checklist
Before you power on:
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Wall brackets mounted level
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Line sets connected snugly (no visible leaks)
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Drain line pitched downward
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Wall hole sealed with caulk or putty
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Electrical connections confirmed with breaker off
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Thermostats paired with SmartHVAC app
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Tested heating and cooling for both zones
🔗 External Verified Resources
In the next topic we will know more about: What’s New in the 5th Gen MRCOOL Mini Split? Upgrades That Matter for Savvy Buyers
