Which of the following is a common refrigerant found in modern HVAC systems?

R-410A is widely recognized as a common refrigerant in modern HVAC systems, particularly because of its efficiency and environmentally friendly properties. It has replaced older refrigerants such as R-22, which are being phased out due to their high ozone depletion potential and environmental impact. R-410A operates at a higher pressure than R-22, which allows for better energy efficiency and improved performance in heating and cooling applications.

The widespread adoption of R-410A is also due to its non-ozone-depleting characteristics, making it a more sustainable choice in compliance with environmental regulations. This transition reflects a broader movement within the HVAC industry towards more eco-friendly refrigerants that contribute to reducing the overall impact on the environment.

In contrast, R-22 and R-12 are phased-out refrigerants with significant environmental concerns linked to ozone depletion. R-134A, while also an alternative, is primarily used in automotive applications and is less common in the HVAC sector compared to R-410A. Thus, the prominence of R-410A in today's HVAC systems highlights its role in advancing energy efficiency and sustainability in the industry.