Written by Grove Collaborative

Ask an expert: Should you wash your clothes in cold water?

Last updated: August 28,2020

See how making the switch from warm to cold water on laundry day can help save you money (and your clothes) while reducing your carbon footprint.

Here at Grove, we're big believers in saving the planet with science — and without sacrificing products' effectiveness. To break down how natural and sustainable products manage to stack up against the competitors without questionable chemicals, we're grilling our scientists, doctors, and fellows for easy-to-understand primers and explanations on how products work.

Old habits can be hard to break — like more than 60% of Americans still washing their laundry in warm water. The mindset that warmer temperatures result in cleaner clothes has been passed from one generation of laundry doers to the next. But with the advent of High Efficiency (HE) washers and specially formulated laundry detergents, low-temperature wash cycles are much more effective than they were 10 years ago.

According to The New York Times, on average, American households do about 300 loads of laundry every year. Just making the switch from hot to warm water can cut your energy usage in half. Imagine if you switched to cold water? Not only would it help the environment, but it would also save you money. Read on for the lowdown on making this simple change, with tips from Clement Choy, Ph.D., Grove Collaborative fellow and senior director of science and formulation.


What's the difference between warm water and cold water laundry?

Water temperature is simply a measure of how quickly molecules move: The warmer the water, the faster the particles zoom around. Using warm or hot water to wash clothes was once the norm, but water temperatures have been decreasing over time, with the temperature for warm-water wash dropping by 15°F over the past 15 years.

Temperature is only one of four components used to clean clothing effectively. You also need to factor in overall wash time, the mechanical action of your machine, and the type of laundry detergent you're using.

"The whole idea of having an HE machine is that you're cutting down on the water and so increasing the concentration of the detergent, and it's always a longer cycle," says Choy. "Using a more concentrated product with reduced water over a longer washing time all drives to the fact that you can get by with colder temperatures."

Water temperatures for laundry

Cold Water

low 40s–60°F

Warm Water

90°F

Hot Water

120°F or above

Expert Tip

Make the switch to HE

About 90% of the energy the washing machine uses goes towards heating the water. "Even though HE machines are almost always a longer cycle — at least 45 mins to an hour, and sometimes beyond — the energy consumption of running an hour is far less than heating up the water," says Choy.

How do cold water laundry detergents work?

Cold-water laundry detergents are specially formulated with enzymes and surfactants that work exceptionally well in temperatures traditionally reaching as low as 60°F (although today, they can work in temperatures as low as the 40s). These enzymes effectively break down stains to allow surfactants and functional ingredients to work their magic.

"We try to use ingredients, surfactants and otherwise, that are at least as effective in cold water as they are in warm water, and we optimize the enzyme system and maximize the percentage so we're combining the enzymes and the dosage," says Choy. Each enzyme targets a different kind of stain:

  • Protease – protein-based stains
  • Amylase – starch or carbohydrate stains
  • Cellulase – breaks down cotton fibers to release dirt
  • Mannanase – food-based stains
  • Pectinase – fruit-based stains

Choy also notes, "Enzymes are a key part of the equation. But other drivers also help cold-water washing, anything from placing less in your machine to increasing wash times."

Sustainability Tip

A household could cut its emissions by 864 pounds of carbon per year by washing four out of five loads in cold water.

When should you wash clothes in cold water?

It may be surprising to learn that not all stains respond well to warmer water. For example, hot water can set blood or sweat stains into fabric. So even though it's okay to use enzymes in warm or hot water ("they won't start degrading until the water is very hot, and even then, it's a slow degrading," says Choy), you may want to still opt for cold water depending on what sort of stains you're tackling.

Cold water can remove many different types of stains, including grass and makeup, and also prevents them from setting in and becoming permanent. And, delicate fabrics such as lace and silk favor cooler, gentler temperatures. Cold water also protects clothes from fading, shrinking, and transferring color to other garments while washing.

A detailed study by researchers at the University of Kentucky found that cold water resulted in the lowest degree of pilling, too. Colorfastness of jeans and khakis is highest in cold water, and cold-water loads exhibited the highest degree of smoothness for reduced wrinkles.

Cold water laundry tips

Dos

  • Sort according to care label
  • Pretreat stains

Dont’s

  • Don’t overstuff your washer
  • Don't use too much detergent, it can leave residue on clothes

Sustainability Tip

If every household in the U.S did just one load per week in cold water instead, we would save 2.3 million metric tons of CO2e. This is the equivalent of the amount of carbon captured by 2.2 million acres of forest.

When should you still wash clothes in warm or hot water?

Saving energy and money is great, but does cold water kill all those nasty germs in the laundry? The cold-water process will remove dirt, stains, and some bacteria from a load of laundry, but it will not kill germs. However, this is true of washing clothes at any water temperature. Unless you have a washer with a sanitizing cycle, the water doesn't get hot enough. Only a disinfectant will sanitize the laundry and the machine.

That said, if someone in your household is sick or you are washing soiled diapers, hot-water washing followed by high-heat drying is your best bet. If the dryer reaches 135°F, it can significantly reduce the number of bacteria and viruses on your clothes. However, it is essential to note that much depends on the length of the drying cycle, the fabric, and the type of bacteria or virus. This method also kills dust mites as well as lice.

Shop laundry


Looking for more cleaning how-tos and other sustainable swaps you can make at home? Grove has you covered. From timely topics such as our handwashing and hand sanitizer breakdown to evergreen primers like our simple ways to reduce your plastic use at home, our handy guides are here to answer your most pressing questions. And let us know how if you have any cleaning questions (or share your own tips using #grovehome) by following Grove Collaborative on Instagram, Facebook, Twitter, and Pinterest.

If you're ready to take on laundry, shop Grove Collaborative's laundry essentials for the detergents and tools to tackle the job.

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