The development of technologies such as the Internet of Things (IoT) and cloud computing has greatly improved the living environment. The Building Research Institute of the Ministry of the Interior of Taiwan also utilizes smart building data to improve the intelligence and humanity of buildings and meet the needs of modern people in the smart-life era. The greenhouse effect, extreme weather, and smog make people more susceptible to weather conditions. To satisfy the health/comfort specifications required for buildings in Taiwan to be awarded smart building marks, technologies such as IoT, AI, and big data are imported to meet people’s needs for a comfortable indoor living space. A temperature and humidity sensor, air quality sensor, and gas sensor are used to obtain the indoor physical environment index. An environmental control system for a smart household is established through Arduino in this study to provide a low-cost and highly smart environmental monitoring and sensing system. A micro-algorithm mechanism is used to start adjustable devices, and mobile phone interface apps are utilized to convey the environmental conditions in real time and regulate the operation of household appliances so as to improve the comfort of the indoor space and provide a comfortable and protective environment for work and living.