Thermal comfort: standard compliant modelling of natural ventilation in adaptive time step solvers. Natural ventilation can help maintain thermal comfort during summer periods. In simulation models for thermal comfort analysis, occupant behaviour related to natural ventilation is often included through definition of ventilation rule sets, included in building codes such as DIN 4108-2. For example, windows are opened when room temperature exceeds a given limit while at the same time outside temperatures remain below a threshold. However, these rules were so far defined with respect to fixed step time integration methods. Straight-forward implementation of such rules in error controlled adaptive time step integration solvers (e.g. included in THERAKLES, DELPHIN, COMSOL, MODELICA-solvers etc.) fails. The article discusses strategies and model variants that work with such modern solvers and discusses new model parameters such as the delay time or dead-band size. The impact of these parameter choices is illustrated with sensitivity studies using the thermal room model THERAKLES.