Embodied energy is the energy required to build a product from raw material. It takes into account the individual components of the product and the energy requirements to manufacture it. The embodied energy is viewed as a life cycle assessment, where the materials derived from nature are tracked through the manufacturing process, product development, eventual disposal and return back to nature.
A house or office building has a large amount of embodied energy. All the parts of the building require raw materials from nature, such as timber, aluminum, and glass. The energy required to manufacture the individual parts, such as the roof, windows, and floor, adds to the total embodied energy of the structure.
Transporting the individual parts from the factory to the work site requires additional energy. The trucks and machinery required to move the parts, as well as the manpower required to operate the equipment, all add to the total energy of the building. Another factor is the fuel required to operate the trucks and equipment.
Installing the parts of a house or building at the work site also adds to the energy total. The tools and materials used to connect the parts, such as a hammer, nail, or bolt, require energy to manufacture. Workers constructing the building also contribute to the overall embodied energy.
After construction, the maintenance that goes into operating the building also adds to the embodied energy. Parts that need replacement will be manufactured using additional energy. Repairs also utilize raw materials, especially when replacing roofs or adding a driveway.
Once the structure has performed to its limit or natural lifespan, the deconstruction and recycling of the materials occurs. This also adds to the embodied energy of the structure. Energy is required to demolish the building, load trucks with debris, and transport the material to a disposal site. This is generally the last bit of energy that is considered when determining the total energy requirement of a structure.
Generally, the lower the embodied energy of a structure, the more environmentally friendly. It is recommended to build houses with materials that have less impact on the environment. For example, a floor constructed with timber requires less energy than a floor constructed with concrete. Also a roof constructed with corrugated galvanized steel requires more energy than a roof that is constructed with concrete tiles. The overall energy to construct a home should be as low as possible.