## Economical Pond Pump

Does that mean that over time the 550 watt pump will save money? Not necessarily. Pumps are only warrented for one or two or three years, generally. If you live in an area where electricity is cheap and the pumps you are considering are warranted for a year or two, then the added cost of the energy efficient pump, and its replacement, may be greater than the energy costs it will save over the same time period.

If, on the other hand, you live where the cost of electricity is high and you are looking at a pump with a three year warrenty that uses significantly less electricity than the other, then the energy efficient pump may more than pay for its extra up-front cost over the long term.

How to know? A Life Cycle Cost Analysis. Find the cost of electricity in your area, figure how long the pump should last, (generally at least two times the warranty), the number of watts it runs on and do the math. Here’s an example.

Say your pump uses 550 watts/hour and you plan to have it running continuously. It has a warranty of two years, so figure it will last four. 550 watts per hour in one day amounts to 13,200 watts. Divide that by a thousand to get kilowatts; 13.2. Multiply that by 365 days in a year = 4,818. Multiply that by 4 years = 19,272 kilowatts over its lifetime. Multiply that by the cost of electricity in your area, say $.20 = $3,854.

Do the same for the 850 watts/hour pump and the result is $5,957. There is a difference in energy costs of usage over their lifetime between the two pumps of $2,102. The difference in purchase price of the pumps will be in the vicinity of $200.00.

Does this mean the energy efficient pump is the most economical over time? In this scenerio it does, which assumed a twenty cent energy cost, a lifetime of four years and continuous running for all of that four years, yes. If the pump is run half that time, say 12 hours a day or six months of the year the energy differential would drop to $2,901, still a considerable savings. Reduce the life time to two years or run the pump for less often and the difference will be still less. In some areas the cost of electricity is much less so the cost of running the pump will be much less.

Let’s look at the same scenerio as the first example above, but instead of an energy cost of twenty cents per kilowatt, we’ll assume eight cents per kilowatt. We’re looking at a pump that uses 550 watts/hour, running continuously. It has a warranty of two years, so figure it will last four. 550 watts per hour in one day amounts to 13,200 watts. Divided by a thousand to get kilowatts gives us 13.2 per day. We multiply that by 365 days in a year = 4,818, and that by 4 years = 19,272 kilowatts over its lifetime. Now we multiply that by $.08 (eight cents) per kilowatt and we have a total cost over four years of $1,541.76 for the 550 watt pump and plugging in the 850 watt number in place of the 550 we get $2382.00 over four years. A difference of about $840.00. Reduce the life of the pump to two years and you have a difference in running costs over that two years of $427.00.