Q1:How to change the water temperature?
A1:There is a built in mixing valve that is in the white box under the sink . You set the water temp from there.
Q2:Does this touchless faucet come with small handle to keep using it if batteries fail?
A2:No. But you only need to replace the battery, it will resume to use at once.
Q3:How long will the batteries last?
Q3:It depends on your battery supplier. (Alkaline batteries have a longer life and batteries are not included in the package.)