Continuous monitoring of Biogas installations is a means to improve safety and detect failures occurring only under specific operational conditions. Stationary methane sensor networks are able to perform this task by providing temporarily and spatially resolved data on methane concentrations. Therefore, the reliability and precision of the concentration data of individual nodes is paramount. This contribution presents the setting up of such a wireless gas sensor network based on a miniaturized, photoacoustic methane detection approach via multi-unit calibration. The results highlight the importance and potential of reliable calibration methods as basis for gas flux measurements using stationary sensor nodes.