The massic heat capacity c(p) = (partial derivative h/partial derivative T)(p) of 1,2,2,2-tetrafluoroethane (refrigerant R134a) was measured at 18 temperatures from 253 K to 523 K at pressures between 40 kPa and 30 MPa. The Joule-Thomson coefficient mu(JT) = (partial derivative T/partial derivative p)(h) Of this substance was measured al six temperatures from 333 K to 423 K at pressures up to 20 MPa. The R134a probably has no ozone depletion potential. Its global warming potential is about one-tenth of that of the refrigerant R115 (C2F5Cl) for which it can be a substitute as a working fluid in energy technologies.