Temperature perturbations in a LED lighted museum showcase

Due to their thermal capacity, the museum building and the showcases filter the external temperature variations. It is a system box in box. Usually, the exposed objects are lighted by a lighting system installed inside or outside the showcase. Recently, LED lights are used inside museum showcases because they favor the view and do not heat the environment in the showcase. But is it true that the microclimate is not perturbed? In order to answer to this question the temporal trend of the temperature has been measured inside and outside a lighted showcase with LED lights.