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Ask Dr. Laundry

Ask Dr. Laundry

Washing clothes in coldwater

By Dr. Laundry September 20, 2006

I received a smart question from a reader this week and thought I’d address it. Thanks for sending Sean!

The question was in response to my last entry on body soil. With the coldwater detergents on the market these days, there’s often a balance between energy savings vs. cleaning power since the detergent mitigates coldwater instead of the hottest water recommended for the fabric.

My experience has always shown when washing, the warmer the temperature the better for stain/soil removal and cleaning.

Overall laundry performance always goes from (best) HOT > WARM > COLD (poorest).

My recommendation is to use the warmest water listed on the fabric care label. Detergent manufacturers have some flexibility in changing formula ingredients to improve performance under specific conditions. However, there is no way for these chemical changes to make up for the decrease in performance when dropping the wash temperature. In fact, laundry tests that I ran showed using coldwater detergent in warm water gave significantly better performance than when used in cold water. This is true with all detergents I have tested.

Due to the large amount of oily components in body soil, one should strongly consider washing in hot water to get the best removal possible. Even better, add some Clorox Regular-Bleach with the detergent to kick the performance up another notch. Look at those microscope images from the last post to see the difference.

Adding Regular Bleach can make up for a lot of the drop in overall detergent cleaning power. However, even this great laundry additive can not increase performance to the point that washing in cold water with Regular Bleach would have the same performance as washing in hot water.

There’s one final fact to consider. Not all items are equally soiled. So, a compromise is in order. Consider bumping up the wash temperature and adding Regular Bleach for loads with sheets and underwear. For the rest of your everyday items, wash them in the cool water if they look clean. Another tip, consider using or adding a small amount of powdered detergent. Powdered detergents always clean better than liquids due to the ingredients used. If you follow this approach, ALWAYS be sure the powder is dissolved before adding the clothes to the washer. The name-brand powder detergents have gotten better at dissolving in recent years. A couple of ways to do this: start with hot water setting, add powder as machine fills, swirl agitator until water level reaches 1/4-1/3 of agitator fin height, then switch setting to cold and then start adding clothes. If using combo liquid/powder, start with hot water setting, first add powder with liquid detergent as the machine fills, swirl agitator until water level reaches 1/4-1/3 of agitator fin height, then switch setting to cold and then start adding clothes.

This is a little extra effort, but the boost in performance and absence of powder spots when you pull them from the dryer will be worth it.

Let me know how this works if you’ve tried the coldwater detergents.