The AIR-4 from C.A.P. has all the features of the AIR-3 with the addition of independent temperature and humidity controls. An additional outlet is provided which will power equipment only during the night cycle. To conserve CO2, the CO2 outlet is automatically disabled while the temperature/ventilation equipment is running. The AIR-4 is rated for 15 amps @ 120 volts. 3 year no hassle warranty.