The type of refrigerant used in an HVAC system affects the charge verification process due to its unique properties, such as boiling point, pressure, and density. For example, R-410A has a higher pressure than R-22, requiring different charging procedures and equipment. Refrigerants with lower boiling points, like R-134a, may require more precise temperature control during charging. Understanding the properties of the refrigerant being used is crucial for selecting the appropriate charge verification method and ensuring accurate results.