New household refrigerators and freezers can be factory charged with

• A. R22
• B. R404A
• C. R600a, R290
• D. R134a

Answer: (C)

Modern domestic refrigeration focuses on refrigerants with very low environmental impact and safe handling in consumer appliances. R600a (isobutane) and R290 (propane) fit this goal well because they have no ozone depletion potential and very low global warming potential, helping manufacturers meet environmental rules and improve efficiency. They’re used in small sealed systems, and the charge is kept limited to manage flammability risk, which is acceptable in household units with proper safety standards. In contrast, refrigerants like R22 are being phased out for ozone depletion concerns, R404A has a high global warming potential and is mainly used in commercial settings, and R134a is being reduced due to environmental impact, so they aren’t the standard choice for new household appliances today.