Are you sweating over how long it will take to replace an AC unit? On average, a residential AC installation can take anywhere from 4 to 8 hours, but several factors can extend this timeframe. This guide will break down the entire process, from preparation to potential delays, ensuring you know exactly what to expect.

Key Insights

  1. Residential Installations: Central AC typically takes 4 to 8 hours.
  2. Commercial Installations: These can take several days to a week.
  3. Factors Affecting Time: Type of unit, home size, existing infrastructure.
  4. Preparation Steps: Initial assessments, and obtaining permits.
  5. Installation Steps: Removal of the old unit, setting up the new one, testing, and calibration.

By the end of this article, you’ll have a clear understanding of the AC installation process and tips to ensure a smooth and efficient experience. Let’s dive into the details.

How Long Does It Take to Install a New AC Unit – Average Time Estimates

Residential Installations

Central AC

Installing a central air conditioning unit in a residential setting typically takes between 4 to 8 hours. If complications arise, such as the need to replace ductwork or upgrade the electrical system, the process can extend up to 1-2 days. These systems require extensive work, including connecting the indoor and outdoor units and ensuring the system is fully integrated with the home’s existing HVAC system.

Window Units

Window air conditioning units are among the quickest to install, generally taking about 2 to 4 hours. This process is straightforward, involving mounting the unit in a window frame and connecting it to a power source. The simplicity of the setup significantly reduces the installation time.

Ductless Mini-Splits

Ductless mini-split systems typically take 4 to 9 hours to install. This involves mounting indoor units on walls and connecting them to an outdoor compressor via refrigerant lines. The time can vary depending on the number of indoor units and the complexity of routing the lines through the home.

Commercial Installations

Commercial installations often take longer due to the larger scale and complexity of the systems. A central air conditioning unit in a commercial building can take several days to a week, depending on the size of the building, the type of system, and the existing infrastructure.

Factors Influencing AC Installation Time

Type of AC Unit

The type of air conditioner significantly impacts the installation time. Central air conditioning systems generally require more time due to the need for extensive ductwork and electrical connections. In contrast, window units and ductless mini-splits are quicker to set up because they do not require as much infrastructure modification.

Home Size and Layout

The size and layout of your home play a crucial role in determining installation time. Larger homes or those with complex layouts often require more time to ensure that the entire space is adequately cooled. Multi-story homes or those with hard-to-reach areas can further extend the installation process.

Existing Infrastructure

Homes with pre-existing, well-maintained ducts and electrical systems will experience quicker installations. If the current infrastructure is outdated or needs significant repairs, this can add several hours to the installation process. For instance, replacing old ductwork or upgrading the electrical panel can extend the timeline significantly.


The location of the air conditioner installation site is another factor to consider. Units in hard-to-reach areas, such as attics or basements, can add extra time to the installation process. Easy access to the installation site can significantly reduce the time needed.

Preparation Time

Initial Assessment

Before installation begins, a thorough assessment of your home is necessary. This involves a site inspection and load calculation to determine the appropriate size of the unit needed. This step ensures optimal performance and energy efficiency of the new air conditioner.

Permits and Regulations

Obtaining necessary permits and ensuring compliance with local building codes can also add to the preparation time. These steps are essential to ensure the installation is performed safely and meets all legal requirements. Depending on your location, acquiring permits can take anywhere from a few hours to a few days.

Air Conditioner Installation Process

Removal of Old Unit

If you are replacing an existing air conditioner, the first step is to disconnect and remove the old unit. This process typically takes a few hours and includes safely disposing of the old unit according to environmental regulations.

Installation of New Unit

The actual installation of the new air conditioner involves several steps:

  • Unpacking and Inspecting: Checking the new unit for any damage.
  • Setting Up: Placing the unit in its designated location.
  • Connecting to Ductwork or Mounting: For central air systems, this includes connecting the new unit to the existing ductwork. For ductless systems, it involves mounting the indoor units.
  • Electrical Connections: Ensuring that the unit is properly connected to the electrical system and that all connections are secure.

Testing and Calibration

System Check

Once the installation is complete, the HVAC professional will perform a series of tests to ensure the system is functioning correctly. This includes checking refrigerant levels and calibrating the thermostat.

Performance Testing

The final step involves running the system to check for proper cooling and making necessary airflow adjustments. This ensures the air conditioner is operating efficiently and effectively cooling your home.

Potential Delays and Issues

Common Obstacles

Several factors can cause delays during the installation process. Weather conditions, such as extreme heat or rain, can slow down the installation. Additionally, unforeseen repairs, like fixing damaged ductwork or addressing electrical issues, can extend the timeline.

Mitigation Strategies

To minimize delays, planning for contingencies and choosing experienced installers is important. Ensuring all necessary permits are obtained in advance and the installation site is easily accessible can also help keep the project on schedule. 

Final Thoughts on AC Installation

The time it takes to install an air conditioner depends on various factors, including the type of unit, the size and layout of your home, and the condition of your existing infrastructure. 

On average, a residential installation can take anywhere from 4 to 8 hours, with potential delays extending this timeline. By understanding the installation process and preparing accordingly, you can ensure a smooth and efficient installation experience.

For personalized advice and to get an accurate estimate for your specific needs, we recommend contacting Bob’s Repair. Our professional HVAC service can assess your home and provide a detailed timeline and cost estimate for your new air conditioner installation.