If you have never had a new air conditioning system installed before, the process can feel like a mystery. A crew shows up, disappears into your home for several hours, and comes out telling you everything is ready to go. But a lot is happening in between those two moments.
Understanding what a proper AC installation actually involves helps you ask the right questions, recognize quality work, and know what to expect on the day of your appointment. In Acadiana, where your air conditioner runs hard for seven or eight months out of the year, getting the installation right makes a real difference in your comfort and your monthly energy bills.
Here is a clear, step-by-step look at how a professional AC installation should go from start to finish.
Step 1: The In-Home Estimate and Load Calculation
A good installation starts before any equipment is ordered. During the estimate visit, a technician should evaluate your home and collect the information needed to recommend the right system.
The most important part of this visit is the load calculation, often called a Manual J. This calculation takes into account your home’s square footage, ceiling height, insulation levels, window placement, and how much sun your home gets. The result tells the technician exactly how much cooling capacity your home needs.
This step matters more than most homeowners realize. An oversized system will cool your home too quickly, shut off before it can remove humidity from the air, and leave your home feeling muggy and uncomfortable. In Acadiana’s climate, where humidity is just as much of a problem as heat, a properly sized system is not optional. An undersized system, on the other hand, will run constantly and still struggle on the hottest days.
The estimate visit is also when the technician notes the location of your existing equipment, checks the condition of your ductwork, and identifies any electrical or access issues that may affect the installation.
Step 2: Arrival, Review, and Setup
On the day of installation, your crew should contact you before arriving. When they get to your home, the lead technician will walk you through the scope of work before anything begins. This is your chance to ask questions and make sure everyone is on the same page.
While you are reviewing the job details, the rest of the crew will begin laying down floor protection throughout your home and getting tools and equipment staged. The existing system will be powered down, and the electrical circuits and any gas supply lines connected to the old equipment will be shut off safely.
Step 3: Removing the Old Equipment
Your existing outdoor condenser contains refrigerant that must be removed before the unit can be disconnected. This cannot simply be vented into the air. Federal law requires that refrigerant be recovered using a certified recovery machine and a sealed recovery tank. 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 from the pad. The indoor evaporator coil, which sits above or below your furnace or air handler, is also removed at this stage.
Step 4: Preparing the Installation Area
Modern air conditioning equipment is larger than older units. The pad your old system sat on may need to be replaced or re-leveled before the new condenser can be set. A composite pad is the right choice here. It is designed to hold up outdoors for the life of the system and does a better job absorbing vibration than a concrete slab, which can crack and shift over time.
The area around the unit should meet any clearance requirements specified by the manufacturer and local code. Your technician will confirm the new unit fits properly in its location or discuss any adjustments needed.
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 along with the outdoor condenser. Pairing a new outdoor unit with an old indoor coil reduces efficiency, can cause refrigerant compatibility issues, and often voids the warranty on the new equipment.
The coil is connected to the sheet metal plenum above your air handler and sealed tightly to prevent air leaks. A properly sealed coil keeps conditioned air from escaping into unconditioned spaces, which is important for both comfort and efficiency.
A condensate drain line is connected to the coil to carry the moisture your system removes from the air to an appropriate drain or condensate pump. This line must be properly pitched, glued, and fitted with a safety overflow switch. If the drain becomes blocked, the safety switch shuts the system down before water can damage your home.
If it has been a while since your ducts were last inspected, this is a good time to ask about duct cleaning as well. Clean ducts help your new system distribute air more efficiently from day one.
Step 6: Running New Refrigerant Lines
The refrigerant lines connect your indoor coil to your outdoor condenser. These lines should be replaced whenever possible. Over time, the oil inside older lines can be incompatible with the refrigerant in a new system, which can cause 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 where they pass through walls or make contact with other materials. A filter drier is installed in the line set to absorb any moisture that could otherwise contaminate the refrigerant system.
The lines are then brazed into the service valves on both the outdoor condenser and the indoor coil. Brazing is a high-heat welding process that creates a tight, leak-free connection. The lines are purged with dry nitrogen during brazing to prevent oxidation inside the copper tubing.
After brazing, the system is pressure-tested using dry nitrogen to check for leaks. If the pressure holds, the system moves on to evacuation.
Step 7: Evacuation and Refrigerant Charging
Evacuation is one of the most critical steps in the process. A vacuum pump pulls air, moisture, and any other contaminants out of the refrigerant lines and coil. The system must reach 500 microns or less and hold that vacuum before refrigerant can be introduced.
Skipping or rushing this step is one of the most common ways a poor installation leads to long-term problems. Moisture left in the system reacts with the refrigerant oil and creates acids that degrade components from the inside.
Once the vacuum is verified and holds, refrigerant is released into the system. The amount is verified and adjusted as needed based on the manufacturer’s specifications.
Step 8: Electrical Connections
The outdoor condenser needs a dedicated electrical circuit with a service disconnect box mounted nearby. A good installation includes a new disconnect box and a new electrical whip connecting the disconnect to the unit. These components protect your system and give technicians a safe way to cut power during future service calls.
The control wiring that allows your thermostat to communicate with the system is also connected at this stage. A new thermostat may be needed if your existing one is not compatible with your new system. Thermostats designed for heat pump operation, for example, have different wiring requirements than a standard AC thermostat. If your electrical panel needs to be updated to support the new system, that work is handled at this stage as well.
Step 9: Startup and Commissioning
Once everything is connected, the system is turned on and allowed to run for 15 to 20 minutes. During that time, the technician takes a full set of measurements to confirm the system is operating within the manufacturer’s specifications.
These measurements include:
- Suction and liquid line pressures and temperatures
- Superheat and subcooling values
- Indoor and outdoor temperature readings
- Return and supply air temperatures
- Static pressure readings throughout the duct system
- Amperage on the compressor, fan motor, and blower motor
- Total refrigerant charge
This commissioning process is the only way to confirm the system is actually performing the way it should. Turning on the unit and watching cold air come out of the vents is not the same thing. A properly commissioned system has a documented baseline that your technician can compare against in future service visits.
Step 10: Cleanup and Walkthrough
When the installation is complete, all old equipment, materials, and debris are removed from your property. Floor protection is rolled up last so that any mess stays contained. Your home should look the same as it did before the crew arrived.
The lead technician will walk you through what was done, explain how your new system operates, review thermostat settings, and go over your warranty information. If you have questions about maintenance or our Shield of Protection membership plan, this is a good time to ask.
How Long Does AC Installation Take?
A standard residential AC replacement typically takes four to eight hours. More complex jobs, such as those requiring ductwork modifications, electrical panel updates, or difficult access to indoor equipment, can take longer. Your technician will give you a more specific estimate once they have assessed your home.
Does a New AC Installation Require a Permit?
Yes. Every new air conditioning installation in Louisiana requires a permit. This is not a formality. The permit process ensures the work meets safety codes and creates an official record that protects you as the homeowner. Any contractor who suggests skipping the permit to save time or money is a red flag.
What to Look for in an AC Installer
The most important things a homeowner can look for are:
- A load calculation performed before any equipment is recommended
- A written proposal that specifies the equipment, refrigerant type, and what is included
- Licensed, EPA-certified technicians
- A full commissioning process with documented measurements after startup
- Proper permits pulled for the work
Cutting corners on any of these steps costs you money over the life of your system. A system that is oversized, improperly charged, or installed with old refrigerant lines will never perform the way it should, no matter how good the equipment itself is.
Ready to Schedule Your AC Installation in Acadiana?
Southern Air has been serving the Acadiana area since 1984. Our installation teams follow a complete process from sizing to commissioning so your new system is set up to perform at its best from day one. We offer flexible financing options and upfront pricing with no surprises.
Call us at (337) 202-5755 or schedule online to get started.
