Heat is given by the formula; IVt, Where I is the current in amperes, V is the voltage in volts and t is the time in seconds.
Therefore; Heat = 3.47 × 129 ×3600 ( 1 hour, has 3600 seconds)
= 447.63 × 3600
= 1611468 Joules
= 1.61 ×10^6 joules in one hour