Experimental design and response surface methodology are useful tools for studying, developing and optimizing a wide range of engineering systems. This tutorial provides a summary and discussion on their use in energy applications. The theory and relevant calculations are clearly presented and discussed along with model diagnostics and interpretation. This is followed by a review of recent reports within the energy field. Overall, this contribution will clarify many aspects of experimental design and response surface methodology that are often confusingly discussed in the academic literature and summarizes relevant applications where they have been found useful.