Cost Per Car

[Earl Weiss]

Reading the recent Car Wash College Tip of the month on figuring solution cost per car, and having heard the methodology before I can't help but wonder why it seems overly complicated and somewhat arbitrary to measure chemical usage for "3 cars" and then figure the cost.
This suggests actual cars. Were they 3 SUVs, or mini coopers? How fast was the line going etc. Why not just have the operator look at their operation and note what the average time is that the relevant arch / equipment runs for what they consider to be an average car at average speed.

Say for example the operator determines an average run interval of 20 seconds. Then, just tell them to turn on that function for 3-5 times that amount, or whatever factor and go from there.

Perhaps even turn it on and then off for the three average intervals in case there is some lag involved to account for.

Wouldn't that be simpler and perhaps a better yardstick?

 

[robert roman]

I have no confidence in the Tip procedure you are referring to, too few measuremetns to draw a meaningful conclusion. With 40 data points, you could perform a Student-T test.

Another method to calculate cost is to collect data for actual carwashes. Measure each product before and after 50 consecutive carwashes. Repeat this for several days or more. With this data, you can calculate average and standard deviation.

 

[DavidM]

I agree that 3 cars is arbitrary and far too small of a sample. I typically use at least 10 cars which still has room for error. I prefer to use actual cars rather than just turning the relay off and on.
Usually this is only when setting up a new product or adjusting. For routine monitoring, I date each drum and when I switch to a new drum I calculate the cars washed from that drum to get a CPC.

David

 

[Earl Weiss]

Excellent point. Something that should be in all cost per car articles etc.

I use this for new setups and a spot check. I believe dating the drum is important to make sure you have no other issues that can affect your costs such as a sticking solenoid valve, sticking relay, leaks, siphons, or even theft, except of coure if the thief ads water to replace what was stolen.

 

[Danny]

I agree with David. The most comon and most simple is counting the cars per container of chemical. You only get an average cost per car meaning you will lose some and win some with each wash. Keeping track if your larger vehicles in you car counts will help you keep track if you are winning or losing more. Dating the container is a very good way to check if you have any consumption issues. Stealing chemicals and adding water has been around forever the good thing is that it gets easy to tell, since thieves are greedy you will be able to see the chemical changing thickness and consistency, becoming thinner.

 

[ted mcmeekin]

Lots of ways to do it but like all such calcs--a large data base is necessary for accuracy. We don't fiddle much--just mark 55gal containers and check after 1000 washes. If we are off a little it is not a significant cost factor. Of course we constantly check wash quality. For our set up, we operate at in 6-9 oz(Soap)/vehicle range. If we are off an ounce--that's about $ .04 or $40 per drum. We are small operation so if we ran many washes we would probably fine tune.


Ted

Ted

 

[Earl Weiss]

Seems the Old adage holds true. As 5 carwashers a question and get 10 opinions, and perhaps all are right!

But, the posts seem to have lost focus on 2 important points.

1. Rather than a random and perhaps not so average sample of 3, 5, or even 10 cars, each location should be able to establish an "average" size car which would include "Average Chain speed" to determine a yardstick of cost per car. Watch your conveyor on a sample day and time the arch "On time" for what you percieve to be the average car / chain speed. Choose that time for an average and multiply it by what you feel would make for a comfortable sample 5X??? Then, simply turn on the function for that amount of time to determine your average usage and cost.
2. If you only monitor large drum useage how would you account for anomolies like stuck solenoids - on or off, controller timeing issues, siphon issues either draw or water return, leaks, theft and dilution?

Or, maybe I just need to get a life.

 

[Reds]

I do a chemical inventory at the end of every month. I measure the amount left in drums in inches, and use a spreadsheet that I have created that converts inches to gallons. I can take begining inventory plus chemical purchases minus ending inventory and come up with a chemical usage for whatever time period I am looking at. Then divide it by the # of cars washed in that same period (which I track on another spreadsheet). I can do this for any period - 1 month, 3 months, annually, whatever. Depending on how you crunch the numbers you can calculate usage in gallons or dollars or both. This method calculates total usage. Theft, spillage, waste, etc. are all included. Total usage. I also do this "line by line" and calculate the usage of each chemical in dollars and gallons.

 

[rph9168]

That would be a really neat spreadsheet. Any way to get a copy?

 

[pitzerwm]

If you would share it, I'll put it in the "How to Do it" section of the Library.

 

[Reds]

Sure I will share it. Let me explain it a little first: I do all my own books, so I have created Excel spreadsheets for reconciling bank stmts, merchant bank stmts, cash control, monthly P&L, sales comps, etc. My monthly inventory (chemical & vending) is a sheet that I have saved as a template - this is the sheet I can share after I add a tab explaining the logic and directions for use. Each month I print page one, take it to the wash on the first, and do my chemical inventory by hand. Then I go home and input the numbers into the spreadsheet. I save this monthend inventory sheet each month in a workbook called "2009 Chemical Inventory". So as the year progresses I have a workbook containing an inventory worksheet for each month. The inventory worksheet calculates my on hand inventory in dollars & gallons. At the end of the workbook I have another sheet called "Usage". This one calculates my usage in dollars & gallons and breaks it down by cost per car. If you have a little spreadsheet knowledge, and grasp the logic underlying the spreadsheet it is easy to use. Since I calculate different time periods (one month, yearly, etc) I have to change some cell references that refer to sheets by month. The only thing I enter by hand is my purchases (in gallons) for the period and my car count. If possible maybe I can post a picture of the monthly sheet and the usage sheet to demonstrate the simplicity of using it. But make no mistake about it - you have to have some basic knowledge of spreadsheet usage. And like all spreadsheets they are only as good as the data that you enter, so I like to double check every entry. And you have to do an accurate month end inventory, which is easy to do.

 

[CarWash College]

Chemical spread sheet

Email me at Randre@carwashcollege.com for an easy to use spread sheet, to track cost on a monthly basis.

 

[variable]

I do a chemical inventory at the end of every month. I measure the amount left in drums in inches, and use a spreadsheet that I have created that converts inches to gallons. I can take begining inventory plus chemical purchases minus ending inventory and come up with a chemical usage for whatever time period I am looking at. Then divide it by the # of cars washed in that same period (which I track on another spreadsheet). I can do this for any period - 1 month, 3 months, annually, whatever. Depending on how you crunch the numbers you can calculate usage in gallons or dollars or both. This method calculates total usage. Theft, spillage, waste, etc. are all included. Total usage. I also do this "line by line" and calculate the usage of each chemical in dollars and gallons.

Same here.