| This article is not about what size of pump to | | | | in the vicinity of $200.00. |
| choose, it is about comparing costs between | | | | Does this mean the energy efficient pump is the |
| pumps of the same size, in terms of their | | | | most economical over time? In this scenerio it |
| up-front cost and running costs. To read about | | | | does, which assumed a twenty cent energy cost, |
| what size pump to choose, see the article on | | | | a lifetime of four years and continuous running for |
| Filtration and Pumps. | | | | all of that four years, yes. If the pump is run half |
| The cost of running a pump is dependant on how | | | | that time, say 12 hours a day or six months of |
| may watts it uses as electricity is measured in | | | | the year the energy differential would drop to |
| terms of kilowatt hours, or the quantity of watts, | | | | $2,901, still a considerable savings. Reduce the life |
| in thousands, used in an hour. The larger the | | | | time to two years or run the pump for less often |
| pump the greater the watts it uses, however | | | | and the difference will be still less. In some areas |
| pumps of the same pumping power can differ | | | | the cost of electricity is much less so the cost of |
| considerably in their watt usage. An energy | | | | running the pump will be much less. |
| efficient pump that delivers 4200 gallons per hour | | | | Let's look at the same scenerio as the first |
| may run at 550 watts while another that delivers | | | | example above, but instead of an energy cost of |
| the same volume of water may run at 850 | | | | twenty cents per kilowatt, we'll assume eight |
| watts. | | | | cents per kilowatt. We're looking at a pump that |
| Does that mean that over time the 550 watt | | | | uses 550 watts/hour, running continuously. It has |
| pump will save money? Not necessarily. Pumps | | | | a warranty of two years, so figure it will last four. |
| are only warrented for one or two or three | | | | 550 watts per hour in one day amounts to 13,200 |
| years, generally. If you live in an area where | | | | watts. Divided by a thousand to get kilowatts |
| electricity is cheap and the pumps you are | | | | gives us 13.2 per day. We multiply that by 365 |
| considering are warranted for a year or two, then | | | | days in a year = 4,818, and that by 4 years = |
| the added cost of the energy efficient pump, and | | | | 19,272 kilowatts over its lifetime. Now we multiply |
| its replacement, may be greater than the energy | | | | that by $.08 (eight cents) per kilowatt and we |
| costs it will save over the same time period. | | | | have a total cost over four years of $1,541.76 |
| If, on the other hand, you live where the cost of | | | | for the 550 watt pump and plugging in the 850 |
| electricity is high and you are looking at a pump | | | | watt number in place of the 550 we get $2382.00 |
| with a three year warrenty that uses significantly | | | | over four years. A difference of about $840.00. |
| less electricity than the other, then the energy | | | | Reduce the life of the pump to two years and |
| efficient pump may more than pay for its extra | | | | you have a difference in running costs over that |
| up-front cost over the long term. | | | | two years of $427.00. |
| How to know? A Life Cycle Cost Analysis. Find | | | | As you see, the less the pump is run, the |
| the cost of electricity in your area, figure how | | | | cheaper electrical energy is in your area and the |
| long the pump should last, (generally at least two | | | | shorter the life of the pump, the less is the |
| times the warranty), the number of watts it runs | | | | differential in running costs between |
| on and do the math. Here's an example. | | | | energy-efficient and non eneregy-efficient pumps. |
| Say your pump uses 550 watts/hour and you | | | | In some cases, when the pump will not be run |
| plan to have it running continuously. It has a | | | | continuously, when it is fairly small and doesn't use |
| warranty of two years, so figure it will last four. | | | | a lot of wattage and the up-front cost of the |
| 550 watts per hour in one day amounts to 13,200 | | | | pumps is significant, it may make more sense to |
| watts. Divide that by a thousand to get kilowatts; | | | | go with the less expensive pump, especially if you |
| 13.2. Multiply that by 365 days in a year = 4,818. | | | | are trying to reduce up-front costs of building a |
| Multiply that by 4 years = 19,272 kilowatts over | | | | pond. |
| its lifetime. Multiply that by the cost of electricity | | | | To know exactly which is the most economical |
| in your area, say $.20 = $3,854. | | | | way for you to go, do the Life Cycle Cost |
| Do the same for the 850 watts/hour pump and | | | | Analysis. It's just arithmetic, so once you've |
| the result is $5,957. There is a difference in | | | | gathered the necessary data and got your head |
| energy costs of usage over their lifetime | | | | around the variables, plug them into the formula |
| between the two pumps of $2,102. The | | | | above and you'll know which way to go. |
| difference in purchase price of the pumps will be | | | | |