An environmental control system (ECS) includes an air cycle machine (ACM), a condenser downstream of the ACM, a reheater between the condenser and the ACM, a primary heat exchanger upstream of the reheater, a first regulated flow path between the condenser and a first environment outside of the ECS, a second regulated flow path between a second environment to be conditioned and the reheater, and a third regulated flow path between the primary heat exchanger and the reheater.