Whether you’re a professional contractor or a handy homeowner, installing a mini split system can be a daunting task. However, it’s not as hard as you think. Compared to traditional forced air AC systems, mini splits don’t require ducts. All they need is a small hole to connect the indoor and outdoor units.
In this article, we go over the steps for installing a ductless mini split, for both DIY and professional contractors. We also provide tips for optimal placement for both the indoor and outdoor units to get the most out of your mini split.
DIY vs Professional Installation
One of the most common questions we get is: “Can I install a mini split myself?”
If you’re a DIYer and thinking of installing a mini split yourself, you’ll be happy to know that yes, it is possible, and doing so can save you money. Whether you are planning on installing a traditional mini split and having a professional come in to charge the system and start it up or going for the even easier option of installing a 100% DIY mini split system, you can reap some pretty serious savings. And to top it all off, you’ll end up saving money in the long run since mini split systems are highly efficient compared to central heat and air.
In order to successfully install your new unit, there are a few key details to keep in mind to make the installation process a bit easier. By taking these factors into consideration, you’ll ensure that your mini split installation is as smooth and successful as possible.
How to Install a Mini Split in 3 Steps
Installing a mini split system can be divided into 3 parts:
- Install the indoor unit
- Install the outdoor unit
- Connect refrigerant piping from the indoor unit to the outdoor unit
Before you begin the installation process, it’s essential to have a few key tools and parts on hand.
Tools & Parts for DIY/Professional Mini Split Installation
A mini split installation will require the following parts for a professional installation:
- Mounting plate*
- Clip anchors*
- Drain joint*
- Wall sleeve*
- Nitrogen Tank
- Hole Saw
- Torque Wrenches
- Vacuum Pump
- Flare Tool
- Tube Cutter
- Allen Wrenches
- Spray-on Leak Detector
- Adjustable Wrench
- Digital Refrigerant Scale
- R410a Manifold Gauges
- Tape Measure
- Line sets*
*Included in a DIY mini split
For a DIY installation, you will only need the following tools to complete installation:
- Hole Saw
- Adjustable Wrenches
How to Install a Mini Split: Step by Step Guide
Install the mounting bracket
- Look for a section of wall free of wires, pipes and ducts.
- Mark the stud locations. Ensure the space behind can be safely drilled.
- Fasten the screws and mount the bracket.
2. Make a pilot hole
- The drilling should be done from the inside to outside.
- While drilling, point the drill slightly downwards to the outside. This slope ensures the line drains properly.
- With the pilot hole done, go outside and check that there are no obstructions for the actual hole.
3. Drill the actual hole
- Using a hole saw, bore from the inside to the outside.
- Once you drill into the wall cavity, pause boring. Inspect the hole for possible lines or obstructions.
- After making sure the path is clear, complete the hole by drilling from the outside.
4. Run the AC line set
- With the hole in place, you can unpack the mini split line set. Uncoil the line from the evaporator.
- From the inside, feed the line through the hole to the outside. We recommend having someone on the outside to help pull and guide the line.
- Carefully bend the line set down to the condenser.
- Make sure the plastic collar at the end of the line set stays in place. This rigid collar helps ensure the line stays connected to the condenser.
- Once all lines have been fed outside, run the drain last.
- Connect the drain extension as necessary. Then wrap it with electrical tape to keep it in place.
- Cover the line set section within the hole with a foam sleeve.
- Replace the insulation in the wall cavity.
Check out our Mini Split Line Sets guide for proper sizing.
5. Install the evaporator
- Place the evaporator on the mounting bracket.
- Ensure it sits snugly on the wall with no play.
6. Install the condenser
- Before mounting the condenser, make sure the line set can reach it easily without routing or obstructions.
- For the electrical part of the installation, check out our dedicated guide: Wiring Specifications for Installing Ductless Mini-Splits & HVAC Units.
- Place the line set so it hugs the exterior wall.
- Double check the minimum clearances for the condenser according to the manual.
- Mount the condenser on the wall or place it on a pad that can support its weight.
- Ensure the final placement area is free from bushes, water or ice accumulation, and other obstructions that can hinder its operation.
7. Connect the refrigerant lines
- Refrigerant lines differ by brand. Consult your manual for the proper steps.
- DIY lines use a locking mechanism to press the line connections together and lock them in place.
- With the lines secured, check that there’s enough length to reach the outside without straining.
- Also look for kinks, sharp bends and other hindrances that can obstruct the flow.
- Power up the system to test the connection.
8. Cover the line set
- Once you’ve verified the mini split is working properly, it’s time to cover the connections.
- Starting from the outside, seal the hole.
- Cover the line set with protective plastic covering or a metal channel.
- Use self-tapping screws to anchor the plastic or metal channel to the wall.
- Test the protective covers for play or looseness. They should be fastened securely to the wall without any movement to ensure years of protection from the elements.
Buying a Mini Split
There are multiple types of mini splits on the market, but only a handful are designed for do-it-yourself installation. MRCOOL DIY mini splits are specifically designed for convenient, easy installation, and the best part? They ship with everything you need to complete the installation! No running to the hardware store to buy last-minute parts and accessories — all you need is a drill and drill bits to install a mini split yourself.
If you are a contractor (or plan on hiring a professional contractor), you have a wider selection of choices. We offer mini splits from renowned brands like LG, Daikin and Panasonic. To determine which model is right for your needs, check out our Air Conditioner BTU Calculator.
In Over Your Head? Call Us for Guidance
If you’re hesitant about installing a mini split yourself, be sure to hire a reputable, qualified HVAC professional who can tackle the process for you. Need some guidance? Call us and we’ll be happy to answer any mini split related questions you may have.