## 4 Discussion  
The results of the energy analysis of popular smart home modules gathered and presented in this paper indicate several important threads, both of a technical and economic nature. First, it should be noted that all smart home modules remain in standby mode 24/7, even when they are not actively used. The collected results (Tables 1-4) show that the modules are constantly consuming low power, to maintain a Wi-Fi connection, for example. This power is negligible, but it loads the supply network all the time. The effect of scale is also important--usually, in home installations with smart home functions, several or a dozen of such modules are installed. For example, a simple scenario of operation of the selected smart home modules in a daily cycle was analyzed, with an analysis of power and energy consumption in the context of the selected control types of loads. The scenario assumes that the lighting circuit is switched on for 8 h and switched off for 16 h per day. There were selected smart home modules with the lowest power consumption with the relay turned off and the location close to the Wi-Fi access point--Sonoff ZBMINI, with average power consumption--tplink Socket, and with the highest power consumption--Blebox Switchbox (based on Table 3). Energy-saving loads were selected as lighting sources: LED lamp 4 Watt and 10 Watt, commonly used in modern home installations as light sources. The results of the analysis are presented in Table 9.  
The analysis of the results indicates that the 24 h power consumption by smart home modules can be significant and contribute to the energy consumption of the electrical installation in a house or building. As can be seen in Table 9, when controlling the 4 Watt LED light source, the energy consumption of the smart home module with the highest power consumption (Blebox Switchbox) can be up to half of the daily consumption of the load itself (8 h on/16 h off). In the case of controlling a larger load, such as the LED lamp 10 Watt, the module's energy consumption slightly increases, but in relation to the energy consumed by the load during 8 h of operation (80 Wh), it is approximately 21%. All these values are for one smart home module and one controlled circuit. Therefore, it is clear that the additional power generated by smart home modules installed so easily and freely in homes should not be underestimated. Hence, certainly the user of the house/building should be aware of it, and especially in the case of larger buildings, the facility manager managing the building infrastructure. At the same time, it should be noted that during communication via Wi-Fi, smart home modules show an increase in power, and thus energy consumption. More intensive communication consumes more energy. Therefore, there is a need to develop a strategy to optimize energy consumption in smart home modules. Research and engineering teams are working on this, especially those related to the manufacturers of such modules [19]. The mechanisms of energy-saving modes or intelligent management of the Wi-Fi connection they are developing can help minimize unnecessary power consumption in standby mode and reduce the time of activity necessary to send/receive control signals. Another very important conclusion from the measurements carried out using the precise PQM-711 power network analyzer is the observed reactive power consumption, both by the smart home modules themselves (very low levels) and by the smart home modules controlling specific loads. In this case, the level of reactive power consumption strictly depends on the type of load and the nominal power of a given electrical device. Reactive power consumption results from the presence of electronic and power electronic components in smart home modules and loads (especially LED lamps), necessary for their proper operation. In the case of a fan receiver, reactive power is related to the design of the electric motor.