This thesis researches the economic and ecologic effects of time window constraints in the distribution logistics of make-to order companies with the help of a simulation based production-distribution planning system. The German industry of kitchen furniture manufacturing hereby serves as a sample population. The thesis will deliver answers, if the cost and ecologic savings on basis of Co2 emissions from a theoretical reduction of time window constraints in unique-make-to-order deliveries, will lead to a change in demand for the setting of time windows, from the receiver of goods to the favor of the supplier. In this respect, this thesis will investigate possible customer perspectives and service elasticities.