With the advance of technologies, design and development of smart houses is becoming a very important area of research applications. The expectations of smart house users are a more rational use of resources, greater security and safety, and increased comfort. In this paper the design and implementation of a reliable and environmental-friendly smart home system is presented. The research project focuses on energy savings, security, safety and increased comfort for the users. The human interaction with the system is achieved through intelligent and user's friendly interfaces, allowing both local and remote control of the house. The entire system is built around an inexpensive microcontroller platform, the Arduino platform, using real sensors and actuators. The local control is achieved through a keypad and an LCD display, while the remote control includes an Arduino Ethernet based micro web-server, and an Android based app, which can be used from any Android supported device. The system is affordable, user friendly and easy to adapt, allowing to add new devices and functions, without altering previously built functions. All the functions of the smart house were tested and are fully functional, proving the feasibility and the effectiveness of the design. A reliability analysis was also performed, using industrial grade CAD tools. Estimating the reliability of various blocks of the system and identifying components based on their failure rates, help the designer to make the necessary changes to the design, choosing more reliable components, incorporating spares or adding fault tolerant features. smart devices to operate reliable. The information collected by various sensors is transmitted in some cases over the Internet (Internet-of-Things). Recent consumer surveys show that people are concerned about privacy and security regarding personal information, but also the vulnerabilities found in home appliances [2]. Estimating the reliability of various hardware blocks of the smart house system and identifying components based on their failure rates, helps the designer to make the necessary changes, choosing more reliable components, incorporating spares or adding fault-tolerant features.Saving electrical energy, gas, water, and other natural resources affects the global environment in a positive way. Preventing fires, smoke and gas leakage avoids polluting the atmosphere. Security systems prevent unwanted intruders, who may damage the property and possibly endanger the environment through malice fires, water floods, etc.There are several factors that need to be considered when designing a reliable and environmental-friendly smart house. The system should be affordable, user friendly and easy to adapt, in order to incorporate new devices and features [1]. Current research in the area of smart house covers usually areas such as: (i) smart home design, covering a broad spectrum of functions from the efficient use of resources to the increased comfort for the inhabitants, offering powerful means for helping and supporting v...