This paper aims to advance the knowledge related to the simulation of electrochromic glazing switching control. First, a critical evaluation of existing control strategies currently available in the DOE-2.1E program was performed to study the effect of several driving variables on the cooling load of an existing large office building. Second, the present capabilities of the DOE-2.1E program were expanded using the Functional Values approach which enables the user to introduce new algorithms (e.g., control strategies) without recompiling the program.