How to decide which pond pump to buy when the pond pumps look
similar but the price is different
First check power consumed by each pond pump
Let's go back first to check how we work out the running cost of a
pond pump assuming you know the Wattage of the pond pump (you will see
this on the pond pump box ... if you only see Amps multiply the Amps by
your Voltage to calculate WATTS approximately).
I know how many Watts my pond pump uses ... How do I calculate
running cost?
In this case calculating the annual running cost for your pond pump
is quite simple.
However first you need to find out how much a unit of electricity
costs in your area (and it can vary a lot by area). A unit of
electricity is normally expressed as a kWattHour or kWhr and it the
amount of money required to run an item consuming 1,000 Watts for 1 hour
or 60 minutes. This information can be obtained by reading your utility
account (electric bill). In USA it varies between about 6c per kWhr and
20c per kWhr. In my country it rarely costs more than 6c per kWhr.
Pacific States USA typical costs in
2004 ... for other states click this
link to website about water
heaters and you will see cost of electric power for each state in USA
-
Alaska
12.75
-
Hawaii
16.59
-
California
-
Oregon
7.06
-
Washington
6.24
You can see therefore that the running cost of a pond pump in Hawaii
is far more important in economic terms than the same pump running in
Oregon. In fact let's do a comparison over a period of 1 year and
remember a good pond pump will last for about 6 years so total cost of
running a pond pump over 6 years is significant. For this exercise
assume the pond pump rated power is 90 Watts ... such a pond pump would
cost about $90 to $120
Hourly power used = 90 Watts = 0.09 kWhr
A complete day's consumption for this pond pump = 24*0.09 = 2.16
kWhrs
After running non-stop for 1 year the pond pump has consumed 2.16 *
365 = 788 kWhr
In Hawaii this would cost 788 * $0.1659 = $130.80 whilst the same
pond pump doing exactly the same job in Oregon would only cost 788 *
0.0706 = $55.66
Over 6 years the same pond pump could cost anything between $785 and
$334 ... this is a big difference and especially when you consider the
pump cost about $90 only
If I live in Oregon and can choose between 2 pumps that will do the
job I want what do I do to make best decision?
Here we will consider only price and running cost for the alternative
pond pumps ... we will assume everything else is identical eg guarantee
Assume both pumps will last at least 3 years.
Total cost of pond pump 1 over 3 yrs is $100 + $( 0.1 * 24 *
365 * 0.0706 * 3yrs) = $285.53
Total cost of pond pump 2 over 3 yrs is $135 + $( 0.065 * 24 *
365 * 0.0706 * 3yrs) = $255.60
Even though pond pump 2 costs 35% more than pond pump 1 the total
cost over 3 years is about 7% less (a saving of about $30).
In Hawaii the saving would be far more on the pump costing $35 more. |
