In the work, we studied the influence of convection on the energy characteristics of coaxial XeCl excilamps driven by a dielectric barrier discharge (DBD). For the study, a special bulb with axially offset outer and inner tubes was manufactured and a gas convection model was developed. It is shown that convection of the mixture can provide an increase of 10–30% in excilamp radiation intensity compared to excilamps with no convection. The presence of convection of the working mixture increases the excilamp lifetime.