What is the most common refrigerant used in small appliances?

The most common refrigerant used in small appliances is R-134a (tetrafluoroethane). This refrigerant is favored primarily for its effectiveness in low-temperature applications, which makes it ideal for household refrigerators and freezers. R-134a is non-toxic and has lower ozone depletion potential compared to older refrigerants, making it suitable for use in smaller appliances that require efficient cooling without posing significant environmental risks.

In contrast, R-22 is primarily used in larger HVAC systems rather than small appliances. While also effective as a refrigerant, it has been phased out in many applications due to its ozone-depleting properties. R-410A, another commonly known refrigerant, contains hydrofluorocarbon and is primarily used in residential and commercial air conditioning rather than small appliances that require the efficiency and specific temperature range R-134a offers. R-404A, a blend of refrigerants, is mostly used in commercial refrigeration settings, not in small appliance applications like refrigerators and small freezers.

Therefore, R-134a's widespread use and compatibility with the cooling requirements of small appliances make it the correct choice.