Hearing in noisy situations is known to be more effortful than in quiet environments for adults and especially for children. Listening effort is defined as the cognitive, attentional, and perceptual processing resources necessary to understand and process speech. This study developed a child-appropriate dual-task paradigm considering aurally accurate sound reproduction to assess listening effort in children and adults. The primary task is a word recognition task and the secondary task is a serial recall task. The influence of different noise conditions on listening effort is studied by examining a no-noise situation and multi-talker babble noise in an anechoic and reverberant environment. In addition, different signal-to- noise ratios (SNRs) are applied. This work presents the first part of the study, where listening effort is examined in adults. The aim is to validate the newly developed child- appropriate paradigm. Consequently, it is expected that the results of the experiment indicate that adults require a higher listening effort in noisy conditions than in the noise-free condition. Additionally, it is studied whether differences in listening effort occur between the noise types and SNRs.