07/16/2026
One of the most important parts of servicing a heat pump is verifying the refrigerant charge correctly—not guessing.
In this video, I’m explaining the basics of using superheat and subcooling measurements to determine whether a system has the proper refrigerant charge. These two measurements work together to give us a much clearer picture of what’s happening inside the system.
As a general guideline, you’ll often see:
• Superheat: 8–12°F
• Subcooling: 10–15°F
Depending on the equipment and manufacturer specifications, those target ranges can vary, but this is a solid foundation for understanding the process.
Typically:
✅ High superheat + low subcooling = system is likely low on refrigerant.
✅ Low superheat + high subcooling = system is likely overcharged.
Of course, there are other factors that can affect these readings, and no diagnosis should ever be based on just one measurement. Airflow, indoor and outdoor conditions, metering devices, and manufacturer specifications all play a role. But understanding the relationship between superheat and subcooling is one of the fundamentals every HVAC technician should master.
At RAFVAC Solutions, we believe in educating our customers and doing things the right way—not cutting corners. A properly charged system runs more efficiently, provides better comfort, and can help extend the life of your equipment.
