Roughly 90 per cent of present-day housing in Germany was built prior to 1977, in other words, before the first thermal insulation regulations came into force in that country. As a result, apart from window modernizations that have possibly been undertaken in the meantime, the construction of most buildings does not meet present-day energy requirements. Bearing this in mind, the technological aspects of facade refurbishment may be considered under the following headings: comfort, construction materials and energy. Frank Hülsmeier, Karl-Heinz Petzinka