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a technician cleaning a mini split

How to Install a Mitsubishi Mini Split System


Mitsubishi is a leading manufacturer of electronic products around the world. Over the past 30 years, Mitsubishi has established itself as a reliable brand that combines modern engineering with innovative designs to deliver high-quality electrical goods. Mitsubishi mini split AC systems are extremely popular in the U.S., and it’s no surprise that they are frequently the best-rated ductless AC system provider for commercial and residential customers. 

If you plan to upgrade your heating and cooling system, installing a mini split offers many benefits. Although they can be more expensive to install than some other traditional air conditioners, mini splits are far more efficient and can save you a lot of money over the long term. 

Because they are ductless, mini splits use approximately 30% less energy than ducted systems, reducing your carbon footprint and utility bills. Mitsubishi appliances are known for their efficiency, with their more efficient mini split systems holding up to a 30.5 seasonal energy efficiency rating (SEER).

Installing a mini split system involves hooking up refrigerant lines, which can be extremely dangerous if a leak occurs. There are also hazardous electrical components, as the unit is hardwired to the electrical panel. If you’re inexperienced with home installations or HVAC systems, it is essential to hire a state licensed professional technician to the installation process. 

Here’s how to choose the right unit for your home and an overview of how your contractor will install your Mitsubishi mini split system.

Choose the Right Size Unit

The first step is to ensure the Mitsubishi split system is the right size for the space. Mini splits are designed to service a specific room or zone size. 

If the unit is too small, it won’t have enough power to treat the entire room, and the device will overwork the motor, increasing your utility bills. Installing an oversized unit can cause the system to short cycle, turning on and off too frequently, driving up costs, and damaging the appliance. 

One way to find the ideal size of a unit, you need to determine the number of British Thermal Units (BTUs) needed for your space. According to Consumer Reports, a general rule is to have 20 BTU per square foot of space for a home with an average ceiling height of 9’. For a small space between 150 and 300 ft², up to a 6,000 BTU system is suitable. But for a large area between 1,200 and 2,000 ft², up to 40,000 BTUs may be necessary. Carefully measure your space to calculate the square footage to ensure the system has the right number of BTUs.

If your home has vaulted ceilings or those that are taller than average, you’ll need a substantially stronger mini split system to account for the increase in room volume. This also applies if there are significant heat gain or loss factors, such as poor insulation, south and west facing windows, large expanses of exposed external walls, cooking appliances, ceiling fans, and more. Consulting a licensed HVAC contractor OR the staff at ComfortUp can help you find the ideal size unit to heat and cool your home efficiently. 

Install the Inside Unit

Once you have found the right size mini split system, your contractor will install the indoor air handler or handlers, depending on whether you have a single zone or multi zone system. They’ll identify an area along the wall where air dispersion is optimal. Typically, 6" to 12" below the ceiling is a good location. It is critical to ensure the handler isn’t blocked or obstructed by anything, such as furniture, shelves, or other fixtures. 

Air handlers are usually mounted onto brackets. The installation expert will use a level to make sure it’s even before they start drilling holes. An uneven air handler will have difficulty draining, leading to potential issues. 

After installing the mount, they’ll drill a hole in the wall to link the refrigerant lines, drain tubing, and control lines. The owner’s manual explains the exact size requirements for the holes. 

The contract will also need to drill a slightly downward hole (for improved drainage) that exits to the house’s exterior. This hole connects the indoor and outdoor units. 

a technician installing an air conditioning unit

Install the Outside Unit

One of the most important aspects of installing the outside unit is to choose the right location. It can be placed on the ground or a mounted stand as long as the surface is even. The area should be free from obstructions close to the unit, such as trees or shrubbery, and the unit must be kept around 2’ from the wall. 

Connect the Refrigerant Lines

The next step is to install the electrical and refrigerant lines. Depending on the model of mini split, the exact instructions can vary. However, if the model comes with pre-charged lines, avoid cutting them to prevent a refrigerant leak. 

A professional technician will connect the right pipe joints to the lines sets on the back of the outdoor unit before hooking up the multi-conductor wiring from the indoor unit to the outdoor unit. The HVAC contractor will also use a Vacuum pump to remove any moisture or impurities in the lines and will conduct pressure tests to ensure there are no leaks. A technician also connects the main control wire to your indoor unit, powering the entire system. 


a technician servicing a mini split


Wide Range of Mitsubishi Mini Split Systems

Mitsubishi mini split systems offer quality, efficiency, and long-lasting heating and cooling for homes and commercial buildings. There is a wide range of options, from 30.5-SEER-rated single zone mini splits to multi zone systems up to 60,000 BTU. The newer range is smart-compatible and can be connected to your Wi-Fi. 

In addition to professional installation, mini split maintenance is key for optimal performance. It’s important to have your appliance serviced annually by a qualified HVAC expert. 

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