An experimental apparatus for evaluating carbon dioxide local heat transfer coefficients during flow boiling has been set up at University of Naples Federico II. In this paper, the local heat transfer coefficient measured is evaluated relative to the measurement error, varying the type and costs of the instrumentation. The analytical analysis has been performed prior to construction of the test facility. The main aim of the work is to provide a methodology that allows one to reach the best compromise between measurement accuracy and financial resources in the selection of the instrumentation.