How can energy be conserved in buildings?

First, we have to consider all the areas where energy is needed in a building: energy that is used for operating the building, such as for space heating, hot water, lighting, etc., probably comes to mind first. But not only these services need energy; the production of building materials, the actual process of construction, any reconstruction or renovation, and finally the demolition of a building all consume energy (this is called "grey energy", because how much energy a material or product contains is not visible to the naked eye).

There are various ways of reducing buildings' resource and energy consumption and thus avoiding negative effects of construction. They can be summarized under the term "sustainable building".

Measures which contribute to energy-efficiency (source: Schulze Darup, adapted)

A high level of thermal insulation, combined with energy-efficient windows, is seen as one of the most effective measures. An additional measure, e.g. for reducing heat losses by airing, is to install a convenience ventilation system with heat recovery. The consumption of electricity can be reduced by using energy-saving devices; the input of grey energy can be influenced by choosing appropriate building materials.

High level of heat protection

Floor slab with insulation layer (source: Arch Wimmer – schulze darup & partner)

Hemp insulation material (source: Christian Gahle, nova-Institut GmbH)

Hemp insulation material (source: Christian Gahle, nova-Institut GmbH; https://de.wikipedia.org/wiki/Dämmstoff#/media/File:Hanfdaemmstoff_CG.jpg)

Energy-efficient windows

Passive-house window in solid timber (source: Sigg Tischlerei, Hörbranz)

Convenience ventilation system with heat recovery

Convenience ventilation system with heat recovery (source: Bin im Garten)

Convenience ventilation system with heat recovery (source: Bin im Garten; https://upload.wikimedia.org/wikipedia/commons/2/22/IFA_2010_Internationale_Funkausstellung_Berlin_104.JPG)