Vocal effort is a physiological entity that accounts for changes in voice production as vocal loading increases, which can be quantified in terms of Sound Pressure Level (SPL). It may have implications on potential vocal fatigue risk factors. This study investigates how vocal effort is affected by room acoustics. The changes in the acoustic conditions were artificially manipulated. Thirty-nine subjects were recorded while reading a text, 15 out of them used a conversational style while 24 were instructed to read as if they were in a classroom full of children. Each subject was asked to read in three different reverberation time RT (0.4 s, 0.8 s, and 1.2 s), in two noise conditions (background noise at 25 dBA and Babble noise at 61 dBA), in three different auditory feedback levels (-5 dB, 0 dB, and 5 dB), for a total of 18 tasks per subject presented in a random order. The subjects answered questions addressing their perception of vocal fatigue on a visual analog scale. Babble noise and the order of task presentation increased SPL and self-reported fatigue. The SPL increased when the RT and the auditory feedback level decreased further clarifying how vocal effort changes within various conditions.