Just for kicks and since I'm an engineer I ran some numbers to try to quantify the difference in running 110 volts versus 220 volts. The bottom line is that 220 volts is a little better choice especially if you have a long run from power source to the motor, and it will run cooler. Here’s why. Let’s say you run a 12 gauge copper wire 100 feet from your breaker box to motor. This wire has a resistance of 0.00187 ohms per foot for a total resistance of 0.187 ohms. Let’s say you are running a generic 1/2 hp motor, it theoretically draws an average of 3.4 amps at 110 volts. The power loss in a wire is I x I x R, where I is current draw and R is total resistance. So in this situation you will lose 3.4 x 3.4 x 0.187 = 2.16 watts of power. Every hour you run the pump you lose 0.00216 kw-hr. If you run continuously you will lose 18.9 kw-hr per year. If you pay the average national rate of 10 cents per kw-hr this line loss will cost you $1.89 per year. Now if you use the same motor but switch it over to 220 volts the current draw is exactly half of that when running at 110 volts which is 1.7 amps. The power loss is 1.7 x 1.7 x 0.187 = 0.54 watts = 0.00054 watts = one fourth the loss at 110 volts. For an entire year you’ve now lost 4.7 kw-hr per year which cost $0.47 per year, again one fourth of what you lose at 110 volts. The difference is small but there is a difference. Now what if you have a 1000 foot run the electricity you waste running that same motor is $18.92 per year at 110 volts and $4.70 at 220 volts. I think this ought to settle the case that no one is wasting much money on buying the kw-hrs by going 110 versus 220 volts unless you have very long distances to run the wires. Ah, but that’s not all you lose. There is also a voltage drop associated with power line length. The voltage drop in the line is V = I x R. I’ll spare the math but for a 1000 foot run and the motor draw we’re talking about you would lose 6.4 volts by the time you got 110 volts to the motor while you lose 3.2 volts running at 220 volts. This is half the voltage drop however it is a bigger percentage of the 110 volt power. You are losing 6% of your 110 volt power and only 1.5% of your 220 volt power. Here’s that ratio of one quarter again. This is a real loss in pumping air that the motor can’t produce since it has less voltage. You will not see this in your electric bill but you will see it in at least 6% and 1.5% less air going into your pond. Maybe more depending upon the deisgn of the motor and pump. What is that air worth? It is worth whatever it would cost to pump it. So in one year at 110 volts and 1000 feet of line you will lose the equivalent of 195 kw-hrs of air pumping due to less efficient motor which cost $19.55. At 220 volts you will lose 49 kw-hrs which cost $4.90. So to sum this up while running a 1/2 hp motor for one year with 1000 foot of 12 gage wire you will pay $14.22 more for electricity and get $14.65 less air. This cost you a total of $28.87 to run 110 versus 220 volts. It all depends on wire size and distance. Another consideration is that you generally never want to lose more than 10% of your voltage when running a motor (it will overheat), if you use 220 volt it may allow you to use a smaller wire size and save wire cost. Again it depends on distance. I think this is correct and I hope it helps.

Gotta get back to fishin!