... ~50C; 20~95%R.H. 11standard:Electrochemistry CO alarm only use to detect CO gas.CO gas is one poisonous gas,without color,without ... heater.So to be safty,we suggest you to install CO alarm in kitchen,wash room,dinning room,bedroom,,garage etc.When ... to change battery once a year.Working current:0.7Ma,Alarm current:<35Ma.It will alarm when CO desity is over 150PPM.