Ventilation heat loss

Ventilation heat loss can be reduced by up to 90 percent, at best by means of a venti-lation system with heat recovery.

Basically the following options are available for thermal renovation.

Low-cost measures: these make sense if the building is mainly in good condition. In this case, low-cost measures can be taken, such as insulating the top-floor ceiling, insulating parts of the basement ceiling, sealing windows and the like. Building services can be improved by, say, insulating pipes. In certain cases it is advisable to overhaul or replace the heating system.
Renovating individual components: this is done if only individual components in the building need replacing. In this case it is essential to work out an overall strategy, so that future construction phases can be matched to the current measures and no additional costs are incurred due to interface problems. As a first step, roof and basement ceiling can be renewed and insulated. A second step involves façade and windows (which should not be implemented separately), and a third step tackles building services.
Comprehensive strategy: in general a complete package of renovation measures should be preferred, as this is the most cost-effective solution. Compared to piecemeal measures, comprehensive renovation is more economical, especially in the long run, because expenditure on interface problems and setting the building site up repeatedly is saved. Then again, the building's owners can relax for several decades after comprehensive renovation, and need not carry out another renovation phase a few years later.