Which type of refrigerant is most commonly used today due to its low environmental impact?

R-134a is recognized for its relatively low environmental impact compared to older refrigerants. Developed as an alternative to R-12, which is a chlorofluorocarbon (CFC), R-134a has a significantly lower ozone depletion potential (ODP). While R-12 has been largely phased out due to its destructive effects on the ozone layer, R-134a became widely adopted due to its favorable thermodynamic properties and compatibility with existing systems.

Though R-22 has been commonly used in the past, it too is being phased out due to its high ozone depletion potential and greenhouse gas emissions. R-410A is another refrigerant that, while environmentally friendly in terms of ozone depletion (as it has an ODP of zero), has a higher global warming potential than R-134a, which is a consideration in the ongoing efforts to reduce climate impact.

Overall, R-134a balances effectiveness and lower environmental harm, making it the preferred choice among the refrigerants listed.