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.
Typical voltage is 120 Volts AC but as many have previously stated your house is only wired for 200 Amps. Each wall socket is normally capable of supplying 20 amps of current while others will supply 30 amps.