Evolution in qualitative demand for future residential and commercial buildings is expressed through very various and, sometimes, non-compatible, tendencies.

However, all these demands have to be satisfied in a common environment of, one more time, different constraints.

The synthesis of both demands and constraints is very specific to national contexts. For example, the concept of "sustainable building" is different from a country to another, depending on the availability of resources (space, water, energy, ... ).

The IEA's Committee on District Heating, Cooling and Combined Heat and Power has been concerned that the integrative technology of district heating and cooling is being overlooked by decision makers in both the IBA, the EU Commission and by the United States DOE. There are myths and misconceptions based, in part, on poorly maintained systems in the Central and Eastern European countries that cloud the real fact that, where based on waste heat utilization these systems are more efficient than the direct use of natural gas.