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.

Another thing to keep in mind: The temperature recommendations on clothing labels represent “the highest spectrum clothes can handle,” said Melissa Hockstad, president and chief executive of the American Cleaning Institute. So you don’t necessarily need to go that hot.

The benefits of cold washing are numerous. One calculation from the cleaning institute, using Energy Star data, estimated that a household could cut its emissions by 864 pounds of carbon per year by washing four out of five loads in cold water.