Which one is more cost effective run 110 volts or 220 volts swimming pool pump?

Answer 1

Whenever you have the electric available to do so, always choose the higher voltage. Reason being if you look at the spec plate on the motor you will see that the amp draw is significantly less when wired for 220.

In some cases depending on the horsepower and the brand the difference can be as much as half. Lower amp draw equates to a cheaper operating cost.

Answer 2

One is no more cost effective that the other. You pay for the amount of wattage that you consume. Wattage is the product of amps x volts. If your pool pump is dual voltage then you will see on the nameplate that the current is twice as much at 110 volts as it is at 220. The consumption of the motor will always be the same wattage no mater which voltage you use. Lets say that the pump is 1 HP. The current at 110 volts is 16 amps. 16 x 110 = 1760 watts. The same HP at 220 volts is 8 amps. 8 x 220 = 1760. As you see the wattage remains constant. Where money can be saved is at higher ampacity loads. The higher the voltage the lower the current means that smaller wire can be used at higher voltages. With copper prices these days it is cost effective to not use the bigger size wire when a smaller size will do.