Introduction

The development of technology has led to a continuous decrease in the energy consumption of different devices. At the same time, the number and variety of such devices per one person, family, and household have increased drastically. Apparently, this is one of the reasons why the energy consumption of all mankind continually increases. Regardless of whether we consume energy as electrical energy in some devices, or use fossil energy for transport or heating of houses, finally, all this converts to low-quality thermal energy. And the last one goes generally to growing up the temperature of Earth. This is one of the reasons why we need to turn more and more attention to see how we consume energy and how to use more and more so-called alternative energy sources.

But we can consider a more personal economical point of view. For all the energy consumption we should pay. If the cost of energy from our everyday energy sources rises, one needs to find ways to save energy and introduce independent energy sources.

During this course, we analyze what may be the main energy outgoings in a household, and how to find the possibilities for the economy of energy. For this, we look closely at what are the main energy-consuming devices or absorbers in an individual household, e.g., electrical devices and heating in Estonia, conditioning in southern Europe, etc. We study how energy consumption is divided into different parts and how to save it. Also, we study what savings can be made using so-called alternative energy sources such as solar panels.

As a model system, we consider the individual household which allows us to find more different ways to discuss energy consumption and the economy. Therefore one should consider that not all the discussed ways are used e.g. in apartment buildings.