Laundry Energy Savings Revealed!

By Brian Stewart

The surprising truth about laundry revealed!

It is probably safe to guess that doing the laundry is not one of the high points of your week. Its a simple task we all do, and millions of loads of laundry are washed and dried every day to keep us all looking our best. While we may not give this routine much thought, we tend to have some preconceptions about the best way to clean our clothes that are not all based in truth — and the truth might surprise you.

We have been routinely conditioned to worry about tough stains in our laundry bin that prevent us from “whiter whites and brighter brights”. We have come to believe that the combination of powerful detergents and washing in very hot water is the only way to get clothes truly clean. As a result, we collectively consume millions of gallons of hot water on laundry.

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75–90% of the energy consumed in clothes washing is for heating water

And, the truth is that washing in cold water is just as effective. Multiple studies from Consumer Reports and others have been conducted on this topic. These studies show that washing in the coldest water available is just as effective as the hottest water that comes from our home water heaters with very few exceptions. This is partly because current laundry detergents have been formulated to work best in cold water, and partly because newer machines are so much better at cleaning clothes. Even tough stains like those from wine, grass, blood and chocolate are effectively removed by washing in cold water. For really difficult stains, a longer wash cycle or pretreating will usually do the trick. Here is a funny video from PGE Switchlabs that shows a test they conducted on washing temperature.

Washing in cold water will save energy and save you money on your utility bills. The energy needed to heat the water for washing is typically 75–90% of the energy required for each load. This can translate to 4 to 8 KWh of energy per load depending on how much water your machine consumes and the starting temperature of your local water and the efficiency of your water heater. The CO2 emissions created by that energy will range from 2lbs to 5lbs per load. The bottom line is that washing in cold water can avoid up to 1/2 ton of CO2 emissions per year for an average household. When you multiply that by 126 million households in the U.S. you quickly understand how this simple decision — cold versus hot water — can eliminate millions of tons of CO2 emissions every year.

The same principle applies for drying laundry. The heater in your dryer is extremely energy hungry. It consumes as much as 20 times more energy than the motor which tumbles the clothes and the fan which moves the air. Drying for longer on very low heat therefore requires less energy. Drying this way will take only a few minutes longer per load to completely dry your clothes — even towels.

Besides saving energy, saving money and producing fewer carbon emissions, there is another very enticing reason to wash and dry on low temperature settings. Your clothes will last longer. The hot water and especially the very hot air that we routinely subject our clothes to is extremely damaging to fabrics. A study published in the Textile Research Journal found that “While cotton can be dried at the relatively high temperatures in clothes dryers without immediate catastrophic damage, serious abrasions and cracking damage occur with repeated dryings.” Researchers found that tumbling wet fabrics with high heat led to severe fiber damage which reduces the strength of fabrics by 25% or more. Drying on low heat or line drying produced much less fiber cracking and also reduced lint production, which is a sign of fiber damage. Washing in cold water and drying on low heat is much gentler. As a result your clothes will last longer and look better which means you will need to replace them less often — another way to save money and energy.

So, turn the temperature down! Set your washer to cold water and set the dryer to low temperature and add 10 or 15 minutes to the drying time. Use the cool down feature on your dryer if you have that option — this will turn the heater off for the last few minutes of drying when your clothes are already warm. If you have a washing machine older than 10 or 15 years, you might want to look into replacing it — the new machines use only about half the amount of water per load. A newer machine will also have a more effective spin cycle to remove more water from the clothes which means less time in the dryer. If you are not convinced about washing and drying at low temperatures, do your own test at home and see if you can tell the difference — I think you will be pleasantly surprised.

Brian Stewart is a sustainability consultant and co-founder of ReplaceNow. Visit to find more ways to slash your carbon emissions and help transition the world to renewable energy.

PGE Video: Consumer Reports: water-to-wash-your-laundry/

Dryer Damage, Textile Research Journal: Energy Saving Tips: 180955459/

Energy Use of Dryer

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