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Last Revised: 5/5/25
Are you tired of window units that barely keep up in the summer – and don’t help at all in the winter? Curious if you can install a ductless mini-split system yourself, or if it’s smarter to call in a pro?
With MRCOOL’s DIY installation mini-split kits surging in popularity across big box stores like Home Depot and Lowe’s, it’s tempting to take on the project solo. But before you grab a drill and get started, there are a few things to know.
Here at Mattioni, we’ve seen countless homes transform their comfort and energy savings with a properly installed mini-split. They’re a smart choice for homeowners looking to eliminate window units, gain better zone control, or condition space without existing ductwork.
In this article, we’ll shine some light on MRCOOL’s DIY mini-split systems and how they compare to a professionally installed alternative. You’ll learn:
- What’s in a MRCOOL kit
- Potential challenges to expect during installation
- How to evaluate your own skill set
- When it’s best to bring in a licensed expert
By the end, you’ll be equipped to decide whether a DIY or professional mini-split installation is the right call for you.
What’s Included in a MRCOOL DIY Kit
One of the biggest points of interest with MRCOOL DIY mini-split systems is that they come as a kit designed to make installation possible for homeowners without HVAC licenses or specialized tools. But while the box includes many of the key components, it’s important to know what’s actually covered – and what you may need to plan for separately.
What You Can Expect to Find in the Box
- Indoor air handler (Wall-Mounted Unit) with mounting plate, built-in coils, and remote
- Outdoor condenser unit
- Pre-charged line sets with quick connect fittings (pre-loaded with refrigerant)
- Communication cable and pre-wired power wire
- Condensate drain hose
- Line set wrap and sleeve
- User manual and installation guide
What’s Not Always Included (But May Be Required)
While MRCOOL DIY kits are very complete, there are a few things you may need to supply yourself or purchase separately:
- Electrical disconnect box
- Mounting pad or bracket for outdoor condenser
- Drill with hole saw attachment (usually 3.5”)
- Weatherproof caulk or sealant for sealing exterior wall penetration
- Tools for cutting and securing line set covers
- Conduit or cable protector for outdoor electrical wires (required by code)
The important takeaway here is that you’ll still need some tools of your own to get the job done. Now, let’s take a closer look at the cost difference between a MRCOOL DIY install and a professional one.
The Cost Savings of MRCOOL DIY vs. Hiring a Pro
Prices included are relevant at the time of publication.
A side-by-side cost comparison of MRCOOL DIY and professional mini-split installations isn’t hard to make sense of: you can save a lot of money by setting up your mini-split on your own. The average 1-2 indoor head installation costs between $4,000 and $12,000 here at Mattioni. And each additional indoor head can add between $4,000 and $6,000 to total costs.
At Home Depot, you can take home a MRCOOL DIY kit with 1 indoor head for anywhere from $1,000 and $2,700. And a kit with 5 indoor heads will set you back about $7,000. The pricing disparity is stark.
For homeowners without ductwork who are tired of their loud, bulky window unit, MRCOOL makes mini-splits more affordable. Combine that affordability with the energy efficiency and zoning capabilities of mini-splits, and purchasing a MRCOOL is an attractive option. However, it’s not a decision to take lightly.
8 Crucial Realities of Installing a MRCOOL DIY Mini-Split
It’s no secret that we’re an HVAC company that would prefer if homeowners opted to hire a pro rather than go the DIY route. That’s true. But we have also had first-hand experience with ordinary people who tried to install their mini split on their own, and ended up calling us anyway.
While the MRCOOL DIY series makes a DIY mini-split installation more accessible, they still come with a fair number of challenges and caveats. Before you purchase a DIY installation mini-split system, it’s important to understand exactly what you’re getting into – and whether it’s the right choice for your home.
1. Choosing The Right Tonnage/BTUs Isn’t Always Straightforward
One of the first and most critical steps is choosing the right tonnage and BTUs. MRCOOL systems are available in various sizes, typically from 0.75 to 4.0 tons and 9,000 to 36,000 BTUs, and choosing the right size depends on more than just square footage. You also have to factor in ceiling height, insulation quality, how much direct sunlight the space gets, and even how many people regularly occupy the room.
If the unit is too small, it’ll struggle to keep up. Too large, and it might short cycle, leading to uneven temperature and excess wear. If you’re transitioning to a mini-split from a window AC unit, then you won’t have any easy point of reference to help you decide on a system size.
While MRCOOL’s product pages offer general guidelines, it’s a smart move to consult with a professional before selecting your system.
2. “DIY” Doesn’t Mean “Easy”
It’s also worth noting that while MRCOOL kits are far more DIY-friendly than most HVAC systems, installation isn’t exactly easy.
You’ll need to mount the indoor unit securely and drill a 3-inch hole through an exterior wall to run the refrigerant lines. The outdoor condenser must be placed on a level pad or brackets, and the line set must be carefully routed, insulated, and covered. You’ll also need to manage drainage, protect the components from the elements, and avoid kinking or overstressing the pre-charged lines.
If you’re handy and patient, it’s doable – but far from a casual weekend project.
3. Local Codes And Warranty Terms Still Apply
Another important consideration is code compliance and warranty protection. In many areas, even a DIY-labeled system must still be installed to code, which may include pulling permits or hiring a licensed electrician. If something isn’t done to code, it may impact your ability to sell your home – or worse, compromise safety.
And while MRCOOL does offer warranties for DIY systems, they still have terms and conditions that must be followed exactly. Incorrect installation or skipped steps could result in a voided warranty, even if the system itself is still under coverage.
4. You’re Largely On Your Own If Something Goes Wrong
If you run into problems during or after installation, support may also be more limited than you’d expect. MRCOOL provides documentation and customer service, but no technician is coming to your house to take a look. You’ll be expected to diagnose problems yourself, and you may end up searching for answers to several questions.
It’s not uncommon for homeowners to call in a professional after struggling with the install, and by that point, you’re paying for help on top of what you already spent.
5. Electrical Work Is A Serious (And Risky) Undertaking
The electrical work required for a MRCOOL system is also worth highlighting. Most models need a 220-volt dedicated circuit and an outdoor disconnect box. That means accessing your main electrical panel, running wire through conduit, and properly grounding everything – none of which is recommended unless you’re experienced with residential electrical systems.
Mistakes here aren’t just about code violations; they can result in serious safety hazards or expensive repairs.
6. Performance Depends On Installation Precision
Even with everything installed, there can still be performance concerns. A mini-split that runs doesn’t necessarily run well.
Improper indoor placement can result in poor airflow. Condensate lines that aren’t angled correctly can leak. If the line set is the wrong length or gets kinked, it can reduce system efficiency or even cause long-term damage.
These are installation issues that might not show up immediately but can seriously affect comfort and utility bills over time.
7. A Poor Installation Can Shorten System Lifespan
Lifespan is another factor to weigh. DIY systems are generally designed for ease of installation, which sometimes means compromises in durability. MRCOOL systems can last a long time when installed correctly and maintained well, but improper installation or missed maintenance steps can reduce their life expectancy.
A professionally installed system, on the other hand, is likely to be built with higher-end components and comes with the added assurance that it’s been sized, charged, and configured by someone with years of experience.
8. Many DIYers End Up Calling A Pro Anyway
It’s worth knowing that many homeowners who start out with DIY intentions end up hiring a pro anyway. Whether it’s the complexity of electrical work, issues with fitting the line set, or problems after installation, a lot of people eventually turn to a contractor for help. In the end, this can mean spending even more than if you had hired a pro from the beginning.
Skills You Should Have Before Installing a MRCOOL DIY Mini-Split
- Mechanical Skills (Using power tools, mounting heavy equipment, measuring, and aligning confidently)
- Electrical Knowledge (Working a circuit breaker panel, installing a 220V circuit, identifying wire types and connections safely)
- Basic HVAC Awareness (Recognizing proper airflow for indoor unit placement, refrigerant line limitations, and condensate drain line routing)
- Problem-Solving & Troubleshooting (Following detailed instructions, logically diagnosing minor issues, and researching when needed)
- Physical Abilities & Safety Practices (Working on a ladder, lifting and positioning heavy components, and sealing wall penetrations securely)
Should You Go DIY or Hire a Pro?
Even with a user-friendly system like MRCOOL, installing a mini-split isn’t one-size-fits-all. For some homeowners, it’s a great way to save money and gain a sense of accomplishment. For others, it can turn into a frustrating, expensive ordeal. Here’s how to tell what route is best for you:
DIY Might Work for You If…
You enjoy rolling up your sleeves and tackling larger home projects. You’re very comfortable with tools, can follow instructions carefully, and you’re willing to take your time to do the job right. DIY installation is most likely a good fit if:
- You have a background in home improvement, or experience with electrical or HVAC work
- You’re comfortable using power tools and working on a ladder
- You don’t mind reading instructions, watching how-to videos, and troubleshooting on your own
- You’re installing a single-zone unit in an accessible space like a garage, office, or spare room
- You’re aware of local code requirements and willing to pull permits or hire an electrician if needed
If this sounds like you, a MRCOOL DIY kit could be a cost-effective and satisfying project.
You’re Probably Better Off Hiring a Pro If…
You value convenience, peace of mind, and guaranteed performance – or the technical details are a bit overwhelming. A professionally installed system might be the better route if:
- You’re planning a multi-zone setup (which is more complex and time-consuming)
- You’re not confident working with high-voltage electrical connections or routing refrigerant lines
- You’d rather not risk a voided warranty due to a misstep during install
- You want to ensure maximum efficiency and lifespan from your system
- You don’t have the time or desire to troubleshoot if something goes wrong
In these cases, hiring a licensed HVAC company ensures the job is done right the first time – with full code compliance, proper system testing, and long-term support.
Who Wins: MRCOOL DIY or Professional Mini-Split Installation?
At the end of the day, deciding whether to take on a MRCOOL mini-split install yourself comes down to risk, confidence, and long-term peace of mind. Now that you know what’s included, what’s required, and what can go wrong, you’re prepared to make the right call.
If you’re still unsure, reach out to Mattioni at (610) 400-8510 or book a consultation online. We don’t install MRCOOL, but we do install high-performance ductless systems – and we’ll walk you through what’s involved in a professional installation so you can compare your options clearly.
We’ve helped hundreds of homeowners install their ductless mini-split systems the right way – and we’re here to help you make the most informed decision possible.
