An environmental control system for an aircraft, comprising: an air cycle machine that includes: a compressor disposed on a spool and including a compressor inlet that is fluidly connected to a first heat exchanger outlet of a first heat exchanger through a first conduit, a compressor outlet that is fluidly connected to an inlet of a second heat exchanger through a second conduit, a first turbine disposed on the spool and connected to a first side of the compressor, the first turbine including a first turbine inlet that is fluidly connected to a second heat exchanger outlet through a humidity control system via a third conduit and a first turbine outlet, and a second turbine disposed on the spool and connected to a second side of the compressor, the first turbine outlet is fluidly connected to the humidity control system, a second turbine inlet through a fourth conduit and an environmental control system outlet; a temperature sensor included with the third conduit disposed proximate an outlet of the second heat exchanger, the temperature sensor being configured to provide a signal indicative of a second heat exchanger outlet temperature; an air cycle machine bypass valve disposed within the first conduit and fluidly connected to a first heat exchanger outlet, a compressor inlet, and the environmental control system outlet; and a controller in communication with the temperature sensor and the air cycle machine bypass valve, the controller programmed to, in response to the second heat exchanger outlet temperature being less than a second heat exchanger outlet temperature threshold, while the air cycle machine is operating at a first operating speed and the air cycle machine bypass valve is in an open position, move the air cycle machine bypass valve from the open position toward a closed position; wherein the controller is further programmed to, in response to the air cycle machine bypass valve moving from the open position toward the closed position, increase the air cycle machine speed from the first operating speed to a second operating speed greater than the first operating speed; and wherein in response to an increase of the air cycle machine speed from the first operating speed to the second operating speed, the second heat exchanger outlet temperature increases. an air cycle machine that includes: a compressor disposed on a spool and including a compressor inlet that is fluidly connected to a first heat exchanger outlet of a first heat exchanger through a first conduit, a compressor outlet that is fluidly connected to an inlet of a second heat exchanger through a second conduit, a first turbine disposed on the spool and connected to a first side of the compressor, the first turbine including a first turbine inlet that is fluidly connected to a second heat exchanger outlet through a humidity control system via a third conduit and a first turbine outlet, and a second turbine disposed on the spool and connected to a second side of the compressor, the first turbine outlet is fluidly connected to the humidity control system, a second turbine inlet through a fourth conduit and an environmental control system outlet; a compressor disposed on a spool and including a compressor inlet that is fluidly connected to a first heat exchanger outlet of a first heat exchanger through a first conduit, a compressor outlet that is fluidly connected to an inlet of a second heat exchanger through a second conduit, a first turbine disposed on the spool and connected to a first side of the compressor, the first turbine including a first turbine inlet that is fluidly connected to a second heat exchanger outlet through a humidity control system via a third conduit and a first turbine outlet, and a second turbine disposed on the spool and connected to a second side of the compressor, the first turbine outlet is fluidly connected to the humidity control system, a second turbine inlet through a fourth conduit and an environmental control system outlet; a temperature sensor included with the third conduit disposed proximate an outlet of the second heat exchanger, the temperature sensor being configured to provide a signal indicative of a second heat exchanger outlet temperature; an air cycle machine bypass valve disposed within the first conduit and fluidly connected to a first heat exchanger outlet, a compressor inlet, and the environmental control system outlet; and a controller in communication with the temperature sensor and the air cycle machine bypass valve, the controller programmed to, in response to the second heat exchanger outlet temperature being less than a second heat exchanger outlet temperature threshold, while the air cycle machine is operating at a first operating speed and the air cycle machine bypass valve is in an open position, move the air cycle machine bypass valve from the open position toward a closed position; wherein the controller is further programmed to, in response to the air cycle machine bypass valve moving from the open position toward the closed position, increase the air cycle machine speed from the first operating speed to a second operating speed greater than the first operating speed; and wherein in response to an increase of the air cycle machine speed from the first operating speed to the second operating speed, the second heat exchanger outlet temperature increases.