Windows are central in architecture and they play a significant role in the energy consumption of buildings, particularly in hot climates, where overheating is a critical issue. Innovative glazing technologies, like thermochromic (TC) glazing, could help to overcome those issues. This article aims to identify both the influence and the importance of thermochromic glazing parameters. A sensitivity analysis by means of moment-independent measure with Latin hypercube sampling has been used, taking the uncertainties of the parameters into account, as well as dynamic daylighting and thermal building simulations. The results allow us to put forward the most important set of factors that need to be carefully chosen to design low-energy buildings, with a comfort performance approach. The conclusion of this study provides further knowledge for designers about TC glazing in the early design stage of buildings, for several climates. It demonstrates that the glazing area has the greatest impact on the results, but also several key TC glazing parameters such as the solar or visible transmittance and the switching temperature.