What type of refrigerant is commonly used in most household refrigerators?

R-134a is commonly used in most household refrigerators due to its properties as a low-pressure refrigerant that is efficient and effective for heat exchange. It is a hydrofluorocarbon (HFC) that plays a critical role in modern refrigeration systems as it is non-ozone-depleting, making it more environmentally friendly compared to older refrigerants.

R-22 and R-12 are older refrigerants that have been phased out or are being phased out due to their high ozone depletion potential. R-22, which is still used in some applications, is progressively being replaced due to environmental regulations. R-12 is no longer used in new systems because of its negative environmental impact.

R-410A is another refrigerant that is typically used in newer air conditioning systems rather than household refrigerators. It operates at a higher pressure and is suitable for cooling systems that require greater efficiency, which is why it does not primarily serve as the refrigerant for household refrigerators.

Thus, R-134a stands out as the most suitable refrigerant option for modern household refrigerators, balancing performance and environmental considerations.