Which of the following is NOT typically a characteristic of HFC refrigerants?

HFC refrigerants, or hydrofluorocarbons, are known for their minimal impact on ozone depletion, which is one of the reasons they were adopted to replace older refrigerants that were damaging to the ozone layer. Unlike CFCs and HCFCs, HFCs do not contain chlorine, which is the chemical responsible for ozone depletion. Therefore, ozone depletion potential is not a characteristic associated with HFCs, making it the correct response to the question.

In contrast, many HFCs tend to have higher global warming potentials compared to some natural refrigerants and other alternatives. Their levels of toxicity and flammability are generally low, which is a positive feature contributing to their safety in various applications. Additionally, while HFCs can be efficient, the phrase "higher efficiency" is more context-dependent and can vary based on system design and other factors, but they are often viewed as efficient in many scenarios when compared to their predecessors.