Building physical problems are often the reason for renovations of dwellings. Although methods to rectify the problems are available, the building owners are often unwilling to accept the safest solutions for economical reasons. Practitioners are therefore forced to develop alternative solutions, which are cheaper but only lessens the problem or are less robust in more extreme situations. When alternative renovation solutions are considered, building simulation tools are often used to predict how the different solutions will work. However, depending on the chosen conditions, simulations can be manipulated to show, that almost any solution will work. This mimics the real world; in dwellings one apartment can have a serious mould problem, while another similar apartment is dry, warm and healthy. The reason is often different user behaviour. The dilemma of the practitioner is that some solutions will be sufficient for many users, but some users need safer solutions, which often are more expensive. It is therefore important to explain to the building owner that with the safe solution user behaviour become less important; he buys robustness. Therefore, when new solutions for renovation are considered, the degree of robustness must be considered, and then it is up to the building owner to decide which solution he can afford. The method emphasizes the importance of educating building users, and the safest solution can be seen as insurance, if the education fails. The paper presents examples of renovations based on building physical problems where alternative, less robust solutions have been chosen, based on simulations and tested on pilot projects. Ways to present robustness and to choose pilot projects are also shown.