The starting power of the air conditioner is 2.7 to 3.5 times. Let's take an intermediate value
3 times, the power of 1 horse is equal to 750 watts, and the power of 1.5 horses is calculated
1.5*750 watts = 1125 watts, 1125 watts multiplied by 3 times the starting power. This is the generator power you need. A 6 kW generator is more than enough to power a 1.5 HP air conditioner, and a 2.5 kW Rennes digital inverter generator can start a 1.5 HP air conditioner.