ductless air conditioner

Ductless Air Conditioner Installation: A Step-by-Step Guide

If you’re looking for a more efficient and cost-effective way to keep your space cool, a ductless air conditioner might be the right choice. Unlike traditional central air conditioning systems, ductless systems do not require ductwork, making them a popular option for older homes, room additions, and other unique spaces.

This step-by-step guide will walk you through installing a ductless air conditioner in your home or business. From understanding the components of a ductless system to preparing for installation and mounting indoor units, we’ve got you covered. Keep reading to learn more about the benefits of ductless air conditioners and how to install one for optimal cooling.

Key Takeaways:

  • Ductless air conditioner installation is a cost-effective and efficient way to cool your space.
  • Unlike traditional central air conditioning systems, ductless systems do not require ductwork.
  • Assessing your space and preparing for installation are essential steps for a successful installation.
  • The step-by-step installation includes mounting indoor units, connecting refrigerant lines, and installing the outdoor unit.
  • Professional installation is recommended for safety and optimal performance.

Understanding Ductless Air Conditioners

A ductless air conditioner, a mini-split system, operates differently than a traditional central air conditioning system. Instead of using ducts to deliver cool air throughout a building, a ductless system relies on a series of compact indoor units connected to an outdoor compressor via refrigerant lines.

The indoor units are typically mounted high on a wall and house a heat exchanger and fan, which work together to adjust the air temperature in the room. The refrigerant lines supply the indoor units with chilled, dehumidified air from the outdoor compressor unit.

The compressor unit removes heat from the room air and expels it outside, allowing the cooler air to circulate inside. A ductless air conditioning system is highly efficient, avoiding the energy loss often associated with ductwork in central AC systems.

Assessing Your Space for Installation

Assessing your space before installing a ductless air conditioner is essential to ensure optimal cooling. Factors such as room size, insulation, and existing electrical infrastructure should be considered to determine the appropriate number and placement of indoor units.

Room size is one of the most critical aspects to consider when assessing your space. Depending on the model, a single indoor unit can typically cool an area of approximately 150 to 500 square feet. If you have multiple rooms or larger open spaces, you may need various indoor units.

Insulation is also an important consideration. Poor insulation can lead to poor performance and higher energy bills, so it’s important to ensure your space is adequately insulated before installation.

Your existing electrical infrastructure may also affect your installation options. Where you choose to install your indoor units should be near existing electrical outlets to avoid the additional cost of rewiring.

Sizing Guidelines

When determining the appropriate number and placement of indoor units, you can use sizing guidelines provided by manufacturers. These guidelines are typically based on the size of your space and other factors such as heat load and the number of windows.

Room Size BTU/Hour Required
100 to 150 sq. ft. 5,000 BTU
151 to 250 sq. ft. 6,000 BTU
251 to 300 sq. ft. 7,000 BTU
301 to 350 sq. ft. 8,000 BTU
351 to 400 sq. ft. 9,000 BTU
401 to 450 sq. ft. 10,000 BTU
451 to 550 sq. ft. 12,000 BTU
551 to 700 sq. ft. 14,000 BTU
701 to 1000 sq. ft. 18,000 BTU or more

Following these sizing guidelines will ensure that your ductless air conditioner is energy-efficient and adequately cooling your space, providing comfort all year round.

Preparing for Installation

Before installing a ductless air conditioner, proper preparation is key to ensure safety, efficiency, and optimal performance. Here are some essential steps to take:

  • Secure electrical permits: Before beginning any electrical work, ensure you have the necessary permits from your local governing bodies.
  • Hire a professional installer: It’s critical to choose a reputable, experienced HVAC professional to perform the installation, as a poorly installed system can lead to inefficiency, safety hazards, and costly repairs in the future.
  • Ensure proper electrical requirements: Ductless air conditioners require specific electrical requirements, including dedicated circuits and appropriate voltage. Make sure these requirements are met before installation begins.

By taking these preparatory steps, you’ll be well on your way to a successful, stress-free, ductless air conditioner installation experience.

Step-by-Step Installation Process

Installing a ductless air conditioner may seem challenging, but following a step-by-step guide can make the process effortless.

Mounting the Indoor Units

Begin by measuring and marking the wall where you want to mount the indoor units. Make sure to consider the manufacturer’s guidelines for clearance and placement. Using a drill, mount the indoor unit securely onto the wall. Ensure that the unit is level and secure to prevent any accidents.

Connecting the Refrigerant Lines

Before connecting the refrigerant lines, make sure the outdoor unit is placed within the manufacturer’s recommended distance from the indoor units. Once in place, drill a small hole through the wall where you mounted the indoor unit. Run the refrigerant lines through this hole and connect them to the outdoor unit according to the manufacturer’s directions. Double-check all connections to prevent any leakages.

Installing the Outdoor Unit

Place the outdoor unit on a flat, stable surface. Make sure the unit is level and secure. Connect it to the indoor unit via the refrigerant lines and wiring. Once everything is connected, turn the power to the air conditioner to ensure it works correctly.

With these simple steps, you can install your ductless air conditioner safely and efficiently to enjoy cool, fresh air in your home or office.


In conclusion, installing a ductless air conditioner can be an excellent investment for any space. Not only are these systems efficient and cost-effective, but they also provide optimal comfort and control. It is essential to assess your space, prepare for installation, and seek the help of a professional for a safe and successful process.

By following the step-by-step guide in this article, readers can better understand what goes into a ductless air conditioner installation. From understanding the components and mechanics of these systems to properly sizing and placing indoor units, readers can make informed decisions and enjoy the benefits of a ductless air conditioner in their space.

Remember, proper installation is key to achieving maximum efficiency and safety. Whether a residential or commercial space, a ductless air conditioner can be a great cooling solution for any need. For any questions or help with installation, seek the help of a professional HVAC technician.


What are the benefits of choosing a ductless air conditioner?

Ductless air conditioners offer several benefits, including energy efficiency, flexibility in installation locations, individual temperature control, and improved indoor air quality.

How does a ductless air conditioner work?

A ductless air conditioner comprises an outdoor unit and one or more indoor units. The outdoor unit cools the refrigerant, then circulates to the indoor units through refrigerant lines. The indoor units blow air across the cool evaporator coils, bringing cool air into the space while removing heat and humidity.

How do I assess my space for ductless air conditioner installation?

When assessing your space for ductless air conditioner installation, consider factors such as room size, insulation level, and the layout of your space. You should also evaluate your existing electrical infrastructure to determine the appropriate number and placement of indoor units for optimal cooling.

What preparations do I need to make before installing a ductless air conditioner?

Before installing a ductless air conditioner, you should secure any necessary electrical permits, hire a professional installer, and ensure that your electrical system meets the requirements for installation. It is important to have an expert perform the installation to ensure safety and optimal performance.

What is the step-by-step installation process for a ductless air conditioner?

The step-by-step installation process for a ductless air conditioner includes mounting the indoor units in the desired locations, connecting the refrigerant lines between the indoor and outdoor units, and installing the outdoor unit. It is essential to follow the manufacturer’s instructions and consult a professional for a successful installation.

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