Solid polymer electrolyte fuel cell sensors with different Pt catalyst loading on electrodes were fabricated to measure the ethanol gas concentration in exhaled human breath. The sensitivity, peak current density and charge density for two types of sensors including (i) identical electrode sensors, and (ii) non-identical electrode sensors were measured. The results revealed thatthe GDE with 40% Pt/C—0.3 mg/cm2 loading has the highest sensitivity factor, peak current and charge densities of all types of the sensors studied. The least square coefficients (R2) for almost all of the two types of sensors were found to be acceptable for detecting ethanol concentration with very good accuracy in the BAC range of 0.005–0.2%. The R2 values for peak current densities were as high as the charge densities. Thus, using the peak current density measurement method will be preferable over the charge density measurement method since the latter takes more time for completion of the sensor reading. Utilizing a low Pt containing cathode did not have crucial adverse effect on the sensor’s performance, indicating thatthis type of sensor can be more cost-effective than other types without losing accuracy. Comparison of the performance of the commercial sensor with the fabricated low catalyst loading sensors indicates that these sensors are significantly cheaper and more linear in a wider range of %BAC. Considering all merits of a fuel cell sensor (i.e. sensitivity, high current generation, high linearity response in wide range of%BAC, and low production cost), the sensor with anode loading of 40% Pt/C—0.3 mg/cm2 and cathode loading of 20% Pt/C—0.03 mg/cm2 is the winner. This sensor requires 130 times lower Ptloading compared to the commercial sensor and 67%less Pt loading comparedto the PEMFCsensor studiedby other researchers for ethanol gas measurement.