To calculate the change in temperature, subtract the initial temperature from the final temperature. Example: 84.2 degree Fahrenheit - 41 degrees Fahrenheit = 43.2 degrees Fahrenheit. The temperature from morning to afternoon changed by 43.2 degrees Fahrenheit.
It needs 12 volts so it will be the standard modern power supply provides 12 volts of power.
115 and 230 Volts. The terms 115 volt and 230 volt come from product design standards. Electrical devices are usually designed to operate in this range, plus or minus 10 percent. This makes it easier for homeowners to find an outlet that will power their device.