Competitive cooling with capacitors Current large-scale cooling devices use vapor compression refrigeration. The efficiency of air conditioners has been optimized, but they can be noisy and rely on problematic greenhouse gases. Two groups now present designs for electrocaloric cooling using lead scandium tantalate capacitors that change temperature under an electric field. Y. Wang et al. obtained a very large heat flux using only solid materials and a cooling fan to remove heat from their device. Torello et al. used fluids for heat transfer, leading to a very large temperature difference between the hot side and the cold side. The new designs demonstrate the potential for devices that might be competitive with vapor compression–based appliances with further optimization. Science , this issue p. 129 , p. 125