Is H 134-a the same as R 134-a?

No, H134a and R134a refer to the same refrigerant, which is 1,1,1,2-tetrafluoroethane. The designation "H" is sometimes used to indicate hydrocarbons or hydrogenated compounds, but in this context, it is synonymous with the commonly used R134a label in refrigeration and air conditioning applications. Both terms describe the same chemical compound, which is widely used as a replacement for R12 in cooling systems.