On average, American households do about 300 loads of laundry every year. Heating the water and running the machines can consume enormous amounts of energy, and that means plenty of greenhouse gas emissions.
While efficiency has improved significantly in the past couple decades, one study estimated the nation’s residential laundry carbon dioxide emissions at 179 million metric tons per year. That’s equal to the total annual energy use of more than 21 million homes.
There are steps you can take to reduce those emissions.
“Laundry temperature is a big deal,” said Elizabeth Morgan, director of Innoweaver, a British consulting firm. That’s because about 90 percent of the energy a washing machine uses goes toward heating water.
There are some situations where you probably should use hot water: cleaning bed linens after being sick, for instance, or washing sweaty gym gear. An occasional hot wash can also help with general hygiene, Ms. Morgan said. Aside from that, though, stick to cold water.
It’s worth noting that the cold setting may still heat the water in your machine to as much as 80 degrees Fahrenheit, or about 27 Celsius. Check to see if your washer has a “tap cold” option and, if so, use it.