Is working properly, I listened to your advice and I increased the range between maximum and minimum temperature (27 and 25 ° C) and humidity (50 and 55%).
For the control system I used two relays (http://www.plexishop.it/it/arduino/rele-e-transistor-per-arduino/modulo-1-rele-optoisolato.html) and these also work correctly .
Thank you.