The Complete Guide to DIY Mini Split Installation Posted on October 3, 2024 Mini splits provide an efficient and versatile option for both heating and cooling. However, most mini splits require professional installation by a certified HVAC contractor. Thankfully, DIY mini splits exist for homeowners who are handy. In this guide, we discuss how to install a DIY mini split properly and safely. What is a DIY Mini Split? A DIY mini split is a mini split system designed to be installed by the average to advanced homeowner, without requiring specialized training or tools. Any mini split system that does not specifically say DIY will require special tools, knowledge, and EPA certification to install. One of the biggest hurdles to mini split installation is the refrigerant, which can only be handled and charged by certified professionals. To this end, DIY mini splits use precharged line sets so that homeowners will not need to carry out the refrigerant charging themselves. Another hallmark of the DIY mini splits is that they contain everything necessary to install the mini split, needing only ordinary tools instead of specialist equipment. One such brand is MRCOOL DIY mini splits. The system comes with everything you need to complete the installation — all you need is a drill and drill bits to install the mini split yourself. They use the company’s innovative Quick Connect® Line Sets that allow fast, safe and easy installation of refrigerant lines even by lay installers. DIY mini split systems from MRCOOL are easy to install and require no special tools. By installing the mini split themselves, homeowners can enjoy considerable savings, on top of the long-term utility savings made possible by the mini split’s high energy efficiency. How to Install a DIY Mini Split A DIY mini split consists of four major parts, where the installation process can be divided. These are: The indoor mounting bracket The air handler, also known as the indoor unit The outdoor unit, which contains the compressor The wiring that connect 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. DIY Mini Split Installation: Preparation Before the actual installation, make sure you meet the following conditions: ☑ The indoor unit should be located at least six feet from the floor. ☑ Its position is not blocked by shelving, lighting fixtures, or furniture. ☑ If the outdoor unit is to be installed on a higher floor, it’s better to use a scaffolding or construct one than to use a ladder for safety reasons. ☑ The compressor is free from obstructions such as shrubs and outdoor furniture. ☑ The wall is safe to drill to the outside and free from power lines, communication cables or pipes. Before installing, check out Proper Mini Split Placement to find the best location for your DIY mini split! Tools Needed for DIY Mini Split Installation For a DIY mini split installation, you will only need the following tools: Drill Screwdriver Hole saw Adjustable wrenches Stud finder Level Steps to Install a DIY Mini Split 1. Install mounting bracket Use the included wall template to mark the mounting location. Ensure the template is level using the spirit level. Mark drilling points with a screwdriver. Secure the mounting bracket to the wall using screws. Make sure it is firmly attached and level. 2. Drill outdoor connection Drill a hole through the wall for the line set, drain hose, and electrical wires. Typically, a 2.5 to 3-inch hole is sufficient. Push the included wall sleeve through the wall. Check that the wall sleeve fits properly against the wall. If not, trim with a knife or saw so that it sits flush with the wall. Feed thecommunication wires through the wall sleeve to the outside. Carefully bend the precharged line set to avoid kinks. Run the line set, electrical wire, and drain hose through the hole in the wall. Note that precharged line sets in DIY mini splits should never be cut or trimmed. 3. Install the indoor unit The top of the unit should hook on top of the wall bracket. The bottom of the unit should sit securely in place against the bracket. 4. Install the outdoor unit Place the outdoor unit on a solid base or mounting bracket. Ensure it is level and secure. Attach the drain hose to the appropriate connection on the outdoor unit and ensure it slopes downward to allow for proper drainage. 5. Connect refrigerant line Connect the refrigerant lines from the indoor unit to the outdoor unit. Each refrigerant line comes with colored codes, indicating which ones should be connected. Thread the lines together by hand. Tighten connections with a torque wrench to the specified values. Remove the valve cover on the condenser, use the provided allen wrench to open the valves by turning the wrench counter-clockwise. 5. Electrical wiring Run the electrical wire from the indoor unit to the outdoor unit. Connect according to the wiring diagram provided by the manufacturer. Install an electrical disconnect box near the outdoor unit. Run the electrical wire from your main panel to the disconnect box, following local electrical codes. Connect the power wires from the disconnect box to the outdoor unit. Connect the control wires from the indoor unit to the outdoor unit. Click here for our comprehensive guide to Mini Split Wiring and Electrical Requirements. 6. Secure the connections Wrap the included neoprene cover around the line set. Use sound reducing pads around the refrigerant connections near the air handler. Wrap the deadened lines with the included vinyl tape. 7. Testing Leak check: Use a leak detector or soapy water to test all refrigerant line connections for leaks. System test: Turn on the power and test the system. Verify that the indoor unit is blowing cold air and that the system operates without error codes. Sealing: Seal the hole where the line set passes through the wall with caulk or expanding foam to prevent air and pests from entering. Optional For MRCOOL units equipped with wireless controller function, insert the MRCOOL Smart Controller module into the indoor unit. This allows wireless control of the mini split by phone, tablet, or other Internet-enabled devices installed with the MRCOOL app. Our Recommended DIY Mini Splits Single-zone DIY Mini Split MRCOOL DIY-12 12000 BTU DIY 4th Gen Energy Star Series Single Zone 22.5 SEER Mini Split with Heat Pump The 4th generation of MRCOOL’s renowned DIY mini splits, the latest versions provide incredible energy efficiency and higher cost savings. This 12,000 BTU model has average cooling costs of just around $72 per year, and heating operating costs of about $254 per year. It is Energy Star Certified boasting high ratings including 22.5 SEER and 11.5 HSPF4. The new generation also comes with a SmartController module that allows for Wi-Fi control via phone or tablet. The SmartHVAC app also works with both Amazon Alexa and Google Assistant, allowing for smart home integration and seamless voice control. Also included is a DIY Pro Cable. It is 25 feet and is included with the condenser. It features crimped connectors as well as protective conduit covering for long lasting use. This 12,000 BTU model will cool and heat space that is about 500 sq. ft. or in terms of actual dimensions, a room that measures up to about 22′ x 23′. For larger spaces, 18,000, 24,000, and 36,000 BTU models are also available in our MRCOOL catalog. Price: $1,738.00 MRCOOL DIY-12 12000 BTU DIY 4th Gen Energy Star Series Single Zone 22.5 SEER Mini Split with Heat Pump WiFi SmartController 115 Volt - Choice Line Set Length The only do it yourself (DIY), easy to install mini split air conditioner available. Energy Star Qualified System with Wireless-Enabled Smart C... View Product Dual-zone DIY Mini Split MRCOOL DIY-MULTI2-18HP230C 4th Gen 18000 BTU 21 SEER Configurable Dual-Zone Mini Split This dual-zone mini split compressor can connect to two indoor wall units, totaling 24,000 BTUs. The system’s output capacity is 18,000 BTUs but the system will allow for 24,000 BTU connected capacity. It provides high efficiency, boasting 21 SEER. This is achieved thanks to a DC inverter variable speed compressor that adjusts the compressor based on demand, instead of operating at 100% all the time. The unit also has a Gold Fin condenser designed to resist long term corrosion, making it ideal for those living near the coast. Another feature is its low ambient functionality. It offers 100% cooling operation down to 5°F, which makes it a good choice for server rooms, greenhouses, or applications that require year-round cooling. This compressor can be paired with MRCOOL’s indoor wall and ceiling cassette units. Wall units: 9,000 BTUs (DIY-09-HP-WMAH-230C25) 12,000 BTUs (DIY-12-HP-WMAH-230C25) Ceiling cassette models: 9,000 BTUs (DIYCASSETTE09HP-230C25) 12,000 BTUs (DIYCASSETTE12HP-230C25) Price: $1,372.00 MRCOOL DIY-MULTI2-18HP230C 4th Gen 18000 BTU 21 SEER Configurable Dual-Zone Mini Split Base Price shown is for outdoor unit only. Choose 2 indoor units below with a total connected capacity of 24,000 BTUs (minimum 2 units / 18,000 BTUs). T... View Product Multi-zone DIY Mini Split MRCOOL DIY-MULTI4-36HP230C 4TH Gen 36000 BTU 21.5 SEER Configurable Quad-Zone Mini Split This quadzone compressor boasts 21.5 SEER and can be connected to up to 4 indoor units. It has an output capacity of 36,000 BTUs, but the system will allow for 48,000 BTU connected capacity. Apart from cooling, it also offers 36,000 BTUs of heat thanks to a built-in heat pump. It can be controlled in several different ways: through WiFi using a smartphone app, optional HVAC Ductless Mini-Stat, or the included hand-held remote control. Other multi-zone mini splits from MRCOOL are the tri-zone (DIY-MULTI3-27HP230C) and 5-zone (DIY-MULTI5-48HP230C) models, offering incredible flexibility and hassle-free DIY installation. Price: $2,107.00 MRCOOL DIY-MULTI4-36HP230C 4TH Gen 36000 BTU 21.5 SEER Configurable Quad-Zone Mini Split Base Price shown is for outdoor unit only. You can choose up to 4 indoor units below with a total connected capacity of 48,000 BTUs (minimum 2 units / 1... View Product Your Expert Source for DIY Mini Splits At Total Home Supply, we carry a wide range of DIY mini splits, from complete DIY mini split systems to line sets, controllers, and accessories. We also have the latest 4th generation of MRCOOL DIY mini splits paired with generous warranty coverage. Check out our selection today and enjoy the savings and benefits of an efficient mini split with the seamless convenience of installing it yourself! Mickey Luongo Mickey is the resident heating and air conditioning expert with over 15 years of experience in the industry.