Most homeowners never see what actually happens during an air conditioning installation. A crew shows up, spends several hours working inside and outside your home, and eventually tells you the new system is running. But there is a detailed, multi-step process happening between those two moments, and every step matters.
Understanding what a proper AC installation involves helps you know what questions to ask, recognize quality work when you see it, and spot red flags if corners are being cut. In Baton Rouge, where your air conditioner carries your home through seven or eight months of heat and humidity every year, the installation determines how well and how long your system performs.
Here is a complete walkthrough of what a professional AC installation should look like from start to finish.
Step 1: The In-Home Estimate and Load Calculation
A proper installation starts before any equipment is ordered. During the estimate visit, your technician evaluates your home and collects the information needed to recommend the right system.
The most important part of this visit is the Manual J Load Calculation. This calculation factors in your home’s square footage, ceiling height, insulation, window size and placement, and sun exposure to determine exactly how much cooling capacity your home requires.
In Baton Rouge, this step is especially important because of humidity. An oversized system cools your home too quickly and shuts off before it can remove moisture from the air. Your home stays cool in temperature but feels sticky and damp. An undersized system runs continuously and never keeps up on the hottest days. Proper sizing is the foundation of a comfortable, efficient system.
Any contractor who recommends a system size without first performing a load calculation is guessing. That guess can cost you comfort and money for the life of the system.
Step 2: Arrival, Review, and Setup
On installation day, your crew will contact you before arriving. When the team gets to your home, the lead technician will walk you through the scope of work before anything begins. This review is your opportunity to ask questions and make sure everyone has the same understanding of what will be done.
While you are reviewing the job, the rest of the crew begins laying down floor protection throughout the work area and staging tools and equipment. The existing system will be shut down safely, with electrical circuits and any gas supply lines turned off before any work begins.
Step 3: Recovering Refrigerant and Removing the Old Equipment
Your existing outdoor condenser contains refrigerant that must be removed before the unit can be disconnected. Federal law requires that refrigerant be recovered using a certified recovery machine and a sealed recovery tank. It cannot legally be vented into the atmosphere. Every technician who handles refrigerant is required by law to hold an individual EPA certification.
Once the refrigerant is recovered, the outdoor unit is disconnected from its wiring and refrigerant lines and removed. The indoor evaporator coil, which sits above or alongside your air handler, is also removed at this stage.
Step 4: Preparing the Installation Area
Modern air conditioners are physically larger than older models. The pad your old system rested on may need to be replaced or re-leveled before the new condenser can be set. A composite pad is the right material for this. It is designed to hold up in outdoor conditions for the life of the system and handles vibration better than a concrete pad, which can crack and shift over time.
The technician will also verify that the new unit fits properly in its location and meets any manufacturer clearance requirements.
Step 5: Installing the New Indoor Evaporator Coil
The indoor evaporator coil is the other half of your air conditioning system. It must be replaced together with the outdoor condenser. Installing a new outdoor unit and keeping the old indoor coil reduces efficiency, creates refrigerant compatibility risks, and typically voids the warranty on the new equipment.
The coil is connected to the sheet metal plenum and sealed tightly to prevent conditioned air from escaping into unconditioned spaces. A condensate drain line is connected to carry moisture removed from your air to a floor drain or condensate pump. This line must be pitched correctly, glued, and fitted with a safety overflow switch that shuts the system off if the drain becomes blocked.
Before new equipment goes in, it is worth asking about air duct cleaning as well. Starting with clean ducts means your new system begins moving air efficiently from day one.
Step 6: Running New Refrigerant Lines
The refrigerant lines connect the indoor coil to the outdoor condenser. These should be replaced whenever possible. Over time, old refrigerant lines can contain oil that is incompatible with newer refrigerant types, causing damage if the lines are reused without proper flushing.
New lines are run as straight as possible, secured every four to six feet, and protected at points where they contact other materials. A filter drier is installed in the line set to absorb any moisture that could contaminate the refrigerant circuit.
The lines are then brazed into the service valves on both the outdoor condenser and the indoor coil. Brazing is a high-temperature welding process that creates a tight, leak-free bond. Dry nitrogen is purged through the lines during brazing to prevent oxidation inside the copper tubing.
After brazing, the system is pressure-tested with dry nitrogen to check for leaks. If the pressure holds steady, the system moves to evacuation.
Step 7: Evacuation and Refrigerant Charging
Evacuation is one of the most critical steps and one of the most commonly skipped by installers cutting corners. A vacuum pump removes air, moisture, and any other contaminants from the refrigerant lines and indoor coil. The system must reach 500 microns or lower and hold that level before refrigerant can be introduced.
Moisture left in the system reacts with refrigerant oil and forms acids that degrade internal components over time. A system that was not properly evacuated may run for a year or two before the damage becomes evident as premature compressor failure or refrigerant leaks.
Once the vacuum is verified and holds, refrigerant is released into the system. The charge is verified and adjusted based on manufacturer specifications and real-time measurements.
Step 8: Electrical Connections
The outdoor condenser requires a dedicated circuit and a service disconnect box mounted nearby. A proper installation replaces the disconnect box and the electrical whip connecting the box to the unit. These components protect the system and provide a safe way to cut power during future service calls.
The low-voltage control wiring that allows your thermostat to communicate with the system is connected at this stage as well. If your electrical panel is older or at capacity, updates may be needed to safely support the new system. Electrical updates typically add $100 to $600 to the total project cost and are a normal part of many installations.
Step 9: Startup and Commissioning
Once everything is connected, the system is turned on and allowed to run for 15 to 20 minutes. During this time, the technician collects a full set of measurements to confirm the system is operating within the manufacturer’s specifications.
Measurements taken during commissioning include:
- Suction and liquid line pressures and temperatures
- Superheat and subcooling values
- Indoor and outdoor ambient temperature readings
- Return and supply air temperatures
- Static pressure throughout the duct system
- Amperage on the compressor, outdoor fan motor, and blower motor
- Total refrigerant charge
This process is the only way to confirm the system is actually performing correctly, not just blowing cold air. A properly commissioned system has a documented baseline that future technicians can reference if any issue arises later. Installers who simply turn the unit on and leave when cold air comes out are skipping a step that protects both you and your equipment.
Step 10: Cleanup and Final Walkthrough
When the work is complete, all old equipment, materials, and debris are removed from your property. Floor protection is rolled up last to keep any mess contained inside it. Your home should look the same as before the crew arrived.
The lead technician will walk you through the completed work, explain how to operate the new system and thermostat, and review your warranty information. If you have any questions about maintenance schedules or our Shield of Protection plan, this is the right time to ask.
How Long Does AC Installation Take in Baton Rouge?
A standard residential AC replacement typically takes four to eight hours. Jobs requiring ductwork adjustments, electrical panel work, or difficult indoor equipment access can take longer. Your technician will give you a realistic estimate after reviewing your home’s specifics.
Does AC Installation Require a Permit in Louisiana?
Yes. Every new AC installation in Louisiana requires a permit. This is not optional and is not a formality. The permit process ensures the work meets safety codes and creates an official record tied to the property. Any contractor who suggests skipping permits to save money or time is not operating correctly, and that shortcut can create problems if you ever sell your home.
What to Look for in a Baton Rouge AC Installer
- A load calculation performed before equipment is recommended
- Written proposal specifying the equipment model, refrigerant type, and everything included
- Licensed, EPA-certified technicians
- Permit pulled for the installation
- Full commissioning with documented measurements after startup
Skipping any of these steps puts your comfort and your investment at risk.
Ready to Schedule Your AC Installation in Baton Rouge?
Southern Air has been serving the Baton Rouge area since 1984. Our installation teams follow a complete process from sizing to commissioning, and we pull proper permits on every job. We offer flexible financing and upfront pricing with no surprises.
Check our specials page for any current installation offers, and ask about our Shield of Protection plan to protect your new system from day one.
Call us at (225) 217-6224 or schedule online to get started.
