The pattern of energy use in buildings is strongly related to the building type and the climate zone where it is located. The level of development also has an effect. Today, most of the energy consumption occurs during the building’s operational phase, for heating, cooling and lighting purposes, which urges building professionals to produce more energy-efficient buildings and renovate existing stocks according to modern sustainability criteria. The diversity of buildings, their distinct uses and extended life cycle pose a challenge for the prescription of energy conservation measures. Specific solutions are needed for each situation, such as for the construction of new buildings, for the renovation of existing ones, for small family houses and for large commercial complexes. Energy consumption can be reduced with thermal insulation, high performance windows and solar shading, airtight structural details, ventilation and heat/cold recovery systems, supported with the integration of renewable energy production in the building. These strategies apply to buildings in both warm and cold climates. Site and energy chain planning also influence the energy efficiency of the individual building. However, technological solutions will only be helpful when building occupants are committed to using energy-efficient systems in an appropriate way. There are many factors that influence the energy consumption behavior of individuals, such as gender, age and socio-demographic conditions. Educational and awareness raising campaigns are therefore crucial in the process of ensuring the energy efficiency of buildings.