If you're a homeowner like Tony who's already familiar with the MRCOOL name — or you’re shopping for your first DIY mini split — you’ve probably heard that the 5th Generation MRCOOL DIY System has arrived. And like Tony, you're wondering: What’s different? Is it worth the upgrade?
This guide breaks down exactly what’s new, what’s better, and what still makes MRCOOL one of the most homeowner-friendly HVAC systems on the market.
🔄 A Quick Recap: What Is the MRCOOL DIY System?
The MRCOOL DIY line is a ductless mini split heat pump system that’s:
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❄️ Air conditioner and heater in one
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🛠️ Designed for homeowner installation — no HVAC license needed
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🔗 Powered by Quick Connect® line sets pre-charged with refrigerant
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📱 Controlled via a mobile app, remote, or voice assistant
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🌎 Available in single-zone and multi-zone configurations (up to 5 zones in Gen 5)
Tony first installed a 3rd Gen unit in his garage and was hooked. With the 5th Gen, he’s taking it house-wide — and you might want to, too.
🚀 What’s New in the 5th Generation MRCOOL DIY System?
1. 🌡️ Improved Efficiency Ratings (SEER2, HSPF2)
The new systems are now rated for SEER2 and HSPF2, the Department of Energy’s updated testing standards.
| Metric | 4th Gen DIY | 5th Gen DIY |
|---|---|---|
| SEER2 | ~18.5–20.5 | Up to 22 |
| HSPF2 | ~9.5 | Up to 10.3 |
| EER2 | ~11.0 | Up to 13.0 |
These numbers mean better efficiency, especially under part-load conditions — and that can lower your energy bill year-round.
🔗 Learn more about SEER2/HSPF2 from Energy.gov
2. ❄️ Extended Temperature Operating Range
The 5th Gen condenser can now:
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Cool in temps as high as 122°F
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Heat efficiently in temps as low as –13°F
This makes it much more viable in extreme climates — from Arizona heat to Minnesota winters.
💬 Tony’s take:
“I live in Denver, and my old MRCOOL worked great. But now the 5th Gen doesn’t miss a beat even when it drops below 10 degrees. I haven’t touched my backup space heater in months.”
3. 🔌 Smarter SmartHVAC App Integration
MRCOOL redesigned the SmartHVAC app interface and added new integrations:
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Native support for Google Assistant and Amazon Alexa
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Improved Wi-Fi stability
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Zone naming and real-time energy monitoring
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Enhanced error reporting and remote diagnostics
🔗 Download the MRCOOL SmartHVAC App (Google Play)
4. 🧰 Redesigned Indoor Air Handler
The new indoor units are:
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🔇 Quieter – lower decibel levels in fan mode
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🧼 Easier to clean – better access to filters and coil
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🪟 Slimmer profile – sleeker look on your wall
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📡 Upgraded IR receiver – better remote response
Installation is also easier thanks to a revised mounting bracket that’s more forgiving on uneven walls.
5. 🔧 Better Quick Connect® Coupling System
The 5th Gen uses an improved coupler design that:
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Reduces torque resistance
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Offers clearer thread alignment
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Improves the leak-proof seal
Each line set is still pre-charged with R-410A, and no vacuum pump is needed.
6. 🌐 Expanded Multi-Zone Compatibility
You can now:
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Run up to 5 indoor units off one condenser (up from 4 in most 4th Gen kits)
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Use multiple BTU configurations (9k, 12k, 18k, 24k) in a single system
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Extend line sets up to 75 ft per zone
This makes the system much more flexible for large homes, garages, ADUs, or multi-level layouts.
🧰 What Stayed the Same?
Not everything changed — and that’s a good thing. Here’s what the 5th Gen kept from previous generations:
| Feature | Status |
|---|---|
| Pre-charged R-410A Line Sets | ✅ Still included |
| DIY-Friendly Installation | ✅ Still tool-free for refrigerant |
| 25 ft line sets + extension kits | ✅ Still supported |
| Wall-mount air handlers | ✅ Same size/format |
| Remote controls included | ✅ With all indoor units |
| 7–10 year limited warranty | ✅ Still strong |
🆚 5th Gen vs 4th Gen: Worth the Upgrade?
Let’s break it down:
| Feature | 4th Gen | 5th Gen | Advantage |
|---|---|---|---|
| Efficiency | SEER ~20, HSPF ~9.5 | SEER2 22, HSPF2 10.3 | ✅ 5th Gen |
| Temperature Range | –5°F to 115°F | –13°F to 122°F | ✅ 5th Gen |
| App & Smart Features | Basic scheduling | Energy tracking, Alexa | ✅ 5th Gen |
| Multi-Zone Support | Up to 4 zones | Up to 5 zones | ✅ 5th Gen |
| Ease of Install | Moderate | Slightly improved | ✅ 5th Gen |
Tony’s summary:
“If you already have a 4th Gen and it works great, no rush to upgrade. But if you’re starting fresh or planning for 3+ zones — the 5th Gen is a smarter long-term move.”
🛠 Who Should Consider Upgrading?
✅ New buyers deciding between MRCOOL and another DIY brand
✅ 4th Gen owners wanting better heating in extreme cold
✅ Large home setups with 4+ zones
✅ Homeowners looking for smarter zone control and app features
🧠 Final Thoughts from Tony
“The 5th Gen isn’t just a marketing update — it’s smarter, more flexible, and handles cold like a champ. I’ve installed a few for friends now, and every time it gets easier. MRCOOL keeps getting better without overcomplicating the DIY part.”
In the next topic we will read about: Is a 48,000 BTU Mini Split System Right for Your Home? Sizing for 4 Zones
