Internet of Things (IoT) technologies can facilitate the preventive conservation of cultural heritage (CH) by enabling the management of data collected from electronic sensors. This work presents an IoT architecture for this purpose. Firstly, we discuss the requirements from the artwork standpoint, data acquisition, cloud processing and data visualization to the end user. The results presented in this work focuses on the most critical aspect of the architecture, which are the sensor nodes. We designed a solution based on LoRa and Sigfox technologies to produce the minimum impact in the artwork, achieving a lifespan of more than 10 years. The solution will be capable of scaling the processing and storage resources, deployed either in a public or on-premise cloud, embedding complex predictive models. This combination of technologies can cope with different types of cultural heritage environments. •IoT architecture proposal specific for Heritage Preservation need.•Sensor node life-span of 20 years without battery replacement.•Wireless technology based on subGHz bands capable of passing through tick walls.•Stand-alone sensor based on Sigfox for direct connection to the cloud.•Evaluation done for typical RH and temperature monitoring needs and based on Italian, European and American standards.•All kind of artwork containers covered: single isolated artwork, typical artwork containers (museums, churches, etc.), power supply constrained sites (open-air archaeological sites, etc.).