Installing a new air conditioning system is a big investment in your home’s comfort and energy efficiency. Whether you’re upgrading an older unit or planning a system for a new build, understanding what happens during installation will help you make better decisions, avoid costly mistakes, and ensure your home is ready for the future.
Here’s what you’ll take away from this guide:
- The complete process of a retrofit air conditioning installation
- Key considerations when installing HVAC in new construction projects
- What 2025’s updated standards (SEER2 efficiency ratings and new refrigerant rules) mean for your project
- How to identify the most energy-efficient air conditioning units for new homes
- Practical cost, timeline, and homeowner preparation tips
What Happens During an AC Installation (Retrofit Track)
Replacing an existing unit is one of the most common types of air conditioning installation. For many homeowners, the process can seem overwhelming, but when handled step by step, it’s straightforward.
Arrival and safety preparations
The installation begins with the crew arriving at your home and shutting down power to the system. Safety is critical; this ensures no accidents happen when handling electrical connections or refrigerants.
Removal of old equipment
Your old system is disconnected, and the refrigerant is safely recovered according to environmental regulations. This prevents harmful chemicals from being released into the atmosphere and keeps the job compliant with local codes. The unit is then hauled away, clearing space for the new installation.
Preparing the foundation
If you are installing an outdoor condenser, the pad or base is inspected and leveled. A solid foundation ensures the new unit doesn’t vibrate, shift, or drain incorrectly. For homes without an existing pad, a new one may be poured or a composite pad placed.
Connecting the coil and line set
Indoor and outdoor units must be linked through copper refrigerant lines. Installers carefully measure, cut, and route these lines to avoid leaks or restrictions. The indoor coil, which sits above or inside the furnace or air handler, is then installed and tied into your duct system.
Brazing and evacuation
Connections are brazed (a type of high-temperature soldering) to create airtight seals. The system is then vacuumed with specialized equipment to remove any moisture or air from the refrigerant lines, two things that can damage the compressor if left inside. Once the vacuum test confirms the system is sealed, refrigerant is added to manufacturer specifications.
Wiring the controls
The new unit is wired to your home’s electrical system and connected to the thermostat. Installers also confirm that the control board, relays, and breakers are compatible and working correctly.
Commissioning the system
Commissioning is one of the most important but often overlooked steps. This is when your installer tests and records airflow, static pressure, and refrigerant charge levels. These readings prove the system is running as designed, and they also give you a baseline to compare against in future maintenance visits.
Homeowner walkthrough
Finally, the crew will clean up the site and walk you through the new system’s operation. You’ll learn how to use your thermostat, what maintenance tasks are needed, and how your warranty works. A good installer provides documentation and ensures you’re confident operating your system from day one.
Building New? The New-Construction Track
Installing HVAC in a brand-new home is different from replacing an old system. Instead of fitting equipment into existing ductwork, you get the opportunity to design everything from scratch for optimal efficiency and comfort.
Manual J load calculation
This step determines exactly how much cooling power your home needs. It accounts for your home’s size, insulation, window placement, and even the direction your home faces. Skipping this calculation can leave you with a system that’s either too large (leading to short cycling and wasted energy) or too small (leaving rooms hot and uncomfortable).
Manual S equipment selection
Once the load is calculated, the correct equipment is selected to match that demand. This ensures the system isn’t just powerful enough but also efficient in day-to-day operation. Choosing the right size equipment also extends the lifespan of your air conditioner.
Manual D duct design
Proper ductwork is the backbone of comfort. If ducts are too small, airflow is restricted; if they’re too large, you lose efficiency. Manual D design ensures that every room in the house gets consistent, balanced airflow.
Builder coordination
Air conditioning installation in new construction involves working closely with other trades. Electricians, framers, and insulation contractors must all be in sync. For example, a closet housing an indoor unit must be sized correctly, wiring must be run to support modern systems, and duct runs must be installed before walls are closed.
System balancing and testing
After the system is installed, its balanced airflow is measured and adjusted to keep temperatures consistent in all rooms. This final step ensures the comfort you expect from a professionally designed system.
2025 Changes That Affect Your Installation
The HVAC industry is undergoing major shifts, and homeowners installing systems in 2025 need to be aware of them.
SEER2 efficiency standards
SEER, or Seasonal Energy Efficiency Ratio, measures how much cooling a unit delivers for the electricity it uses. In 2023, new testing protocols called SEER2 were introduced. For 2025, systems in the northern U.S. must meet at least 14 SEER2, while southern states require a minimum of 15 SEER2. This means that even if you’re comparing two systems labeled “15 SEER,” the SEER2 rating may look slightly lower because of the new testing standard.
Transition to A2L refrigerants
Another big change is the shift from R-410A refrigerant to newer, more eco-friendly A2L refrigerants like R-32 and R-454B. These refrigerants are less harmful to the environment and often more energy-efficient, but they also require slight adjustments in system design and installation practices. For homeowners, this means your new unit will likely be A2L-based. Older systems cannot be retrofitted, so replacement units must be chosen carefully.
Being aware of these updates helps you understand why system costs and specifications may look different from what you saw just a few years ago.
These changes especially affect HVAC new construction projects, since builders must plan ahead for efficiency ratings and refrigerant requirements.
Most Energy-Efficient Choices for New Homes
If you’re building a home in 2025, you have more options than ever before for energy-efficient cooling.
Ducted inverter heat pumps
These systems use variable-speed compressors that adjust output in real time, consuming only as much energy as needed. In many climates, they provide both heating and cooling, which can replace or supplement a traditional furnace.
High-efficiency central AC systems
For homeowners who prefer traditional setups, today’s central AC units with ECM blower motors and variable-speed technology offer much better efficiency than older single-stage units.
Smart controls and zoning
Pairing your system with smart thermostats or zoning systems ensures different areas of the home can be cooled independently. This prevents wasted energy in rarely used rooms.
ENERGY STAR® Most Efficient 2025
This designation highlights top-performing systems that meet strict efficiency and performance standards. Choosing one of these units means you’ll enjoy lower monthly bills and may qualify for rebates or tax credits.
Tax incentives and rebates
Federal and local programs are offering financial incentives for upgrading to energy-efficient systems. These can offset upfront costs and make high-efficiency equipment more affordable.
Costs, Timelines & Homeowner Prep
Homeowners often wonder what to expect in terms of cost and disruption during installation.
Timelines
- Retrofit installations usually take one full day, though ductwork adjustments or additional electrical work may extend the job.
- New construction installations happen in phases, coordinated with other trades. The final testing and balancing occur near the end of the build.
Costs
Costs vary depending on system size, efficiency level, and installation complexity. High-efficiency systems and new refrigerant technology may cost more upfront but deliver lower utility bills long term. Permits and inspections are also part of the total investment.
How to prepare your home
- Clear access to work areas indoors and outdoors
- Confirm electrical panels have the capacity for the new system
- Make sure pets are secured for safety
- Be available to discuss thermostat placement or duct adjustments
Frequently Asked Questions
- Can I install an AC myself?
While DIY is possible for window units, whole-home systems require specialized tools, permits, and knowledge. Attempting a DIY installation can void warranties and create safety hazards. - Do I need a permit?
Yes. Most municipalities require a permit and inspection for air conditioning installation. This ensures safety and code compliance. - How long does installation take?
Most retrofit jobs take a day. New construction is spread out over the build timeline. - What commissioning proof should I ask for?
Ask for documentation of airflow, refrigerant charge, and static pressure. This ensures your system is running as efficiently as possible. - Should I consider a heat pump instead of central AC?
For many new homes, yes. Heat pumps provide both heating and cooling, and their efficiency makes them an attractive option, especially when paired with modern insulation and design.
Conclusion
Air conditioning installation has evolved. With stricter efficiency standards, eco-friendly refrigerants, and smarter technology, homeowners today have more to think about than just “cold air in the summer.” Whether you’re upgrading an old system or tackling HVAC new construction, understanding the process gives you confidence and peace of mind.
Fields & Fowler is committed to guiding you through every step of design, installation, and maintenance so your investment delivers comfort and savings for years to come.
Ready to plan your air conditioning installation? Contact Fields & Fowler today to schedule a consultation and discover the best solution for your home.