The collaboration between science and the members of the public often called citizen science can help to make important discoveries about environmental problems. In the Living Lab located in Erzsébetváros, we initiated a participatory research process to be able to more fully understand the urban heat island phenomenon in the district and to capture the perceptions of citizens on the heat stress they have to endure during heat waves. We are launching a citizen-sensing campaign that will measure several components of urban heat waves and urban heat islands (air temperature, humidity, dust, and thermal heat pictures) in the district. With a device that was developed to understand urban heat islands and heat waves, citizens can contribute to well-suited adaptation methods and better policy measures.