Dishwasher Economics

 

As we go through life, there are many points at which we need to make decisions. Some of these decisions are related to the purchase of such items as a home or automobile or others. One of these others is an appliance. Nowadays there are many choices to be made for any given type of appliance. There are various options such as color, size, features etc. In this exercise we will investigate the economics of owning and operating a dishwasher. As you will come to understand, there are many considerations to be addressed in appreciating the evaluation of any product for purchasing consideration. Though we may be viewing a dishwasher here, this process can be applied to virtually any item. One outcome of this laboratory exercise should instill a sense of an investigation through process when mulling over a purchase.

 

Of course for each item, a different set of points of consideration will be in order. When purchasing an automobile, few people first contact their insurance company to determine how this purchase will effect their annual insurance payments. Some of which can be substantial over the life of owing the vehicle.

 

In this exercise, you will determine the actual cost of operating a dishwasher. You may have one, which you currently use and have the related manual as to its specifications or you might have to go shopping for a dishwasher to collect the required information. Although your current use of a dishwasher may be daily or less frequent, make your final cost based on a one load per day as well as an annual cost.

 

Here is a list of items for you to collect and include in your report but it is by no means a complete set of considerations.

 

  • Make and Model number
  • Price (if financing the added interest cost)
  • Expected lifetime of the product
  • Warranty period and/or maintenance contract cost
  • Repair and easement maintenance cost without a service contract
  • Current usage during the various stages
  • Time for each cycle (if not supplied in your manual you can time your unit)
  • Cost of detergent and any drying conditioner
  • Cost of the water itself
  • Cost of heating the water
  • Cost of electricity used (this will vary between the running time if the motor and the cal rod in the drying cycle)
  • Temperature of water coming into the hot water tank and entering the dishwasher

 

After you have collected all of the information complete a full set of calculations including formulas. Due to the cost of some items being small individually, complete all numerical cost values to 5 decimal places and round off only to the cents in your final computation. Organize your report such that it is a logical easy to understand format.

 

 

Here are some useful conversions as well as current coasts as provided by your instructor.

  • Heat of combustion of natural gas ≈ 1000 BTU/ft³
  • 1 BTU = 252 calories
  • 1 ft³ ≈ 7.5 gallons
  • 1 calorie = 4.186 watt-sec
  • Density of water ρ ≈ 64 lbs/ft³
  • P (power in watts) = I (current in amperes) ∙ V (voltage in volts)
  • The cost of water which includes sewer cost in Bonita Springs is 1.5856 cents per gallon.  Some students may say that they have a well. They can use their cost.
  • Electricity price for fuel – first 1000 kWh at 5.841 cents, over 1000 kWh at 6.841 cents; for non-fuel – first 1000 kWh at 4.231 cents, over 1000 kWh at 5.231 cents