1. Regulatory context

The Réglementation Thermique 2012 (or RT 2012) is a French regulatory provision forming part of the package of laws resulting from the "Grenelle de l'Environnement" environmental initiative.

This legislation is part of the more general – national and European – context of greenhouse gas emission reduction targets, which is in turn in line with the 1997 Kyoto Protocol, signed by France and effective as of 2005.

This RT 2012 is only the most recent expression (as its name suggests, it dates from 2012) of a regulation that saw the light of day in the aftermath of the first oil crisis in 1973. The overriding need to limit energy expenditure gave rise to the very first RT in 1977. Increasingly demanding and complex versions followed: RT 88/89, RT 2000, RT 2005.

Each of these versions has raised both the level of requirement...