Thermochemical heat storage offers the possibility to achieve high thermal energy storage capacities compared to sensible and latent heat storage. To quantify this advantage, thermochemical storage systems have to be evaluated under application conditions. The proposed 4-temperatures approach delivers a first step toward a realistic testing of thermochemical working pairs. As an example, the approach is applied to testing the working pair zeolite/water under the conditions of the application of seasonal storage of solar thermal heat for domestic heating purposes.