Environmental balance
The environmental balance of a building is an inventory of all the impacts that it generates on the environment. There are two methods to assess those impacts: the checklist and the Life Cycle Assessment (LCA).
Checklist
The check-list method is a multiple-choice questionnaire combined with a weighting method. It is possible to associate scores reflecting environmental quality with different building criteria. LEED and BREEAM certifications are based on this method.
Life Cycle Assessment (LCA)
The LCA is an environmental impact assessment method that identifies all material and energy flows exchanged with the environment during the building’s life cycle. That is to say during the following stages: construction, operation, renovation and destruction. It then assesses the impacts of each of these flows. This method follows the ISO standards 14040 and 14044.
The flows recorded are of different kinds: incoming or outgoing material flows (raw materials, other materials, consumables, waste, emissions to air, water and land) and incoming or outgoing energy flows (electricity, fuel, heat).
Among the categories of impacts taken into account, the main ones are as follows:
- Global warming
- Destruction of the stratospheric ozone layer
- Rain acidification
- Eutrophication of rivers and water bodies
- Human toxicity
- Air, water and soil pollution
- Reduction of biodiversity
- Resource depletion
The LCA methodology helps to choose one material rather than another for building components, based on the impact it will have on the environment throughout its life cycle.
There are more than twenty LCA tools dedicated to building as well as many inventory databases such as EcoInvent and SimaPro to name only the best-known.
What about the impact of furniture and appliances in the home ?
In addition to the environmental impact specific to the building, the impact of furniture and household appliances in the home should also be taken into account.
According to a study carried out by ADEME, the furniture and equipment of a French household mobilizes about 45 tons of raw materials and emits 6 tons of carbon dioxide. By way of comparison, this represents six round trips from Paris to New York by plane.
The ADEME invites consumers to fight against cultural obsolescence, which encourages people to acquire new goods while old ones are still in use.
The following table details the CO2-equivalent emissions by life cycle stage of several objects in our daily lives (kg CO2):
After analyzing this table, we realize that it is necessary to consider all the stages of a product’s life cycle. For example, if we only consider the step of use of a Smartphone, we might think that it has a lower impact than an electric furnace. However, taking into account the entire life cycle it is not the case. Indeed, the extraction of raw materials emits a lot of CO2-eq emissions.
CO2 emissions at the end of life stage are considered negative due to the avoided production of virgin raw material through recycling.