The low GWP refrigerant of R1234ze(E) is considered to be the prospective candidate alternative to conventional R134a for car air conditioners, while the isomer R1234ze(Z) and R1233zd(E) are anticipated to be the low GWP alternative to R245fa used in high-temperature heat pumps and organic Rankine cycles. The pool boiling heat transfer coefficients (HTCs) of these refrigerants on a horizontal smooth tube made of a copper with an outer diameter of 19.12 mm are quantitatively assessed in this study. The data on surface tension are also presented for R1234ze(E), R1234ze(Z) and R1233zd(E). The observed bubble behaviour and surface tension data support the relativity in HTC. It was confirmed that the experimental HTC closely agrees with the calculated HTC of Stephan-Abdelsalam (1980), Ribatski-Jabardo (2003), and Gorenflo etal. (2010).