Is it worth it to make your own windshield washer fluid?  Is it just a colorized version of alcohol and water?   Are we getting ripped off ?? This week I decided to investigate and spent some time reading a discussion thread on the subject and looking at different mixtures that could be made.  Here are three of the mixtures:

Mixture 1:
3 cups household window cleaner
1 gallon water

Mixture 2:
3 cups rubbing alcohol
4 cups water
2 teaspoons liquid dishwashing detergent
several drops of blue food coloring

Mixture 3:
3 cups rubbing alcohol
10 cups water
1 Tablespoon liquid dishwashing detergent

Let’s look at three important things to consider before you make your own windshield washer fluid:

Do you live where there is snow and freezing temperatures?
If you live in the cold and snow there’s a greater need for a product that works well.  If you don’t have the mix of alcohol and water correct, you risk having it freeze up in your vehicle which could be costly.  If you live in cold temperatures and are making your own fluid, you should put some in your freezer first to make sure it stays in liquid form and doesn’t freeze up.

Is it safe for your vehicle?
In my investigating I found comments by people with knowledge of cars who felt that in the long run, rubbing alcohol could be hard on the hoses in your vehicles.  Apparently the commercial products use methanol, not isopropyl alochol (rubbing alcohol). Some also questioned the wisdom of recipes that used amonia and detergents as they felt it was hard on the car’s paint.

Are the homemade ingredients cheaper?
For me, this is really the crux of the matter.  Let’s look at the prices I found on a trip to Walmart.  The prices below are for the Walmart brands, and not for brands like Rain-X or Windex window cleaner.

$2.50 for a gallon of windshield washer fluid good at -25 below temperatures  (.019 per oz)
$1.64 for a gallon of windsheild washer fluid good at -20 below temperatures  (.012 per oz)
$1.17 for a gallon of windsheild washer fluid good at 32 degree temperatures  (.009 per oz)

$1.12 for 32 oz of window cleaner  (.035 per oz)
$1.67 for 32 oz of rubbing alcohol  (.052 per oz) – this was a sale price

So for mixture #1 above you are going to spend 84 cents on 3 cups (24 ozs) of window cleaner to make your gallon of fluid.  Not too bad if it doesn’t freeze up.

For mixtures 2 and 3 above, you would spend $1.25 on the rubbing alcohol.  However, this is based on the sale price.  Buying the rubbing alcohol at full price would change the savings you are able to realize.

The Bottom Line
It looks like you can make your own mixture cheaper at home using the window cleaner method, if you use a cheap store brand of window cleaner.  However, if you want the assurance that comes with the commercial products (knowing it won’t hurt the vehicle and won’t freeze up) you should watch for a good sale and stock up.

Personally, I like having a few recipes like this in my file so I have the option to make my own if I’m in a pinch.

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