Here’s something most homeowners never hear: the majority of air conditioning systems never actually achieve the SEER efficiency rating they were sold. The reason almost always comes down to one crucial, often-rushed step — the startup.
You paid for a high-efficiency system. The label promised a certain SEER rating. So why is your energy bill higher than expected, and why doesn’t the house feel as comfortable as you hoped? In most cases, it’s not the equipment — it’s how the system was installed and commissioned. And it’s far more common than the industry likes to admit.
The Hard Truth About SEER Ratings
A system’s SEER rating is measured under perfect laboratory conditions. In the real world, most systems fall well short — because they’re not installed and charged to those exact specifications. One study measured real-world central air conditioner performance at just 59 to 84% of rated SEER, and estimates suggest more than 65% of residential systems are improperly installed and performing below their potential.
The biggest culprits are well documented: low indoor coil airflow, an incorrect refrigerant charge, and poor air distribution. These aren’t equipment defects — they’re installation shortcuts. And they quietly cost you efficiency, comfort, and money for the entire life of the system.
Why the Startup Is Everything
Most companies install the equipment, pull a vacuum, release the factory refrigerant charge, and call the job done. The problem is that no air conditioner comes from the factory with the exact amount of refrigerant your specific home and line set require. “Close enough” leaves real performance on the table.
At Air Comfort Technologies, we don’t consider an installation finished until the numbers are dialed in. Here’s how we commission every system:
First, we set the blower airflow and check static pressure — because low airflow is one of the top reasons systems miss their rating. Next, we run the system in cooling for 15 minutes, letting the pressures fully settle so we get an accurate, stable reading. Finally, we dial in the refrigerant charge by measuring superheat and subcooling, charging the system to the manufacturer’s exact specification rather than relying on the factory estimate.
Why does this matter so much? Because the data is striking: charging a system to just 75% of its correct refrigerant level can decrease SEER by 16% and raise your annual operating costs. Getting the charge exactly right is the difference between a system that simply runs and one that delivers the efficiency, comfort, and lifespan you paid for.
What This Means for You
When you’re getting quotes for a new AC system, don’t just compare equipment and price. Ask how the installer commissions the system. Do they set airflow and check static pressure? Do they measure superheat and subcooling and charge to manufacturer specification? If the answer is vague, you may be paying for efficiency you’ll never actually receive. The equipment is only half the equation — the installation is the other half.
If you’re considering a new system in York County, or you suspect your current one was never properly dialed in, we’re happy to take a look and make it right.
Frequently Asked Questions
Why isn’t my new AC as efficient as promised?
Most often it’s the installation, not the equipment. Low airflow, an incorrect refrigerant charge, and poor commissioning cause many systems to perform at just 59 to 84% of their rated SEER. Proper startup — setting airflow and charging to manufacturer specification — is what unlocks the rated efficiency.
What does it mean to commission an AC system?
Commissioning is the process of verifying and tuning a newly installed system: setting blower airflow, checking static pressure, running the system to let pressures settle, and charging refrigerant precisely by measuring superheat and subcooling. It’s the step that ensures you get the performance you paid for.
How do I know if my AC was charged correctly?
A properly charged system has superheat and subcooling readings that match the manufacturer’s specifications, correct airflow, and a temperature split in the expected range. If your energy bills are high or comfort is poor on a relatively new system, an incorrect refrigerant charge is a common cause worth checking.
Want it done right the first time? Air Comfort Technologies commissions every system to manufacturer specification, so you get the efficiency and comfort you paid for. We provide expert AC installation and replacement throughout York County, PA. Call (717) 855-4101 or request a free quote today.