|
Math, dude. Get your power bill and see what you pay for kWh. Look at the wattage of the two pumps you're considering. If they aren't the same flow rate, see how many hours a day you'll have to run them to pump the desired amount of water.
wattage of pump (1000W = 1 kW) times hours on per day give you kWh used per day. Multiple that by your rate and you see your cost per day. Subtract one from the other and you'll see how many dollars per day you'll save. Then you can calculate your time to break even. If it's many years, you may be better off investing the money in your IRA than in a pump- run the numbers and check.
|