Cotton garments can generally withstand hot water, but laundry professionals caution that the decision isn't as straightforward as it seems. Factors like fabric weave, dye type, and your washing machine's actual water temperature all play a role in whether a hot cycle is safe.
Mary Gagliardi, Clorox's in-house scientist and cleaning expert, notes that cotton is a natural cellulosic fiber with strong resistance to high heat from laundering, ironing, or sterilization. However, Frej Lewenhaupt, co-founder and chief product officer at Steamery, a Scandinavian clothing care brand, advises against hot water unless the care label explicitly recommends it. "While it can technically handle hotter temperatures, I wouldn’t recommend washing cotton in hot water unless the care label specifically says so," Lewenhaupt says.
The concern lies in cotton's natural tendency to shrink when exposed to high heat and moisture. Lewenhaupt suggests washing cotton garments in warm water (30°C/86°F) on a gentle cycle for best results. But Gagliardi points out that tightly woven fabrics made with high-twist yarns offer better dimensional stability in hotter temperatures, while loosely twisted yarns and knit constructions are more prone to shrinkage unless pre-shrunk during production.
When Hot Water Makes Sense
For items like white fabrics, t-shirts, socks, underwear, and dress shirts, hot water can be beneficial, especially for brightening and sanitizing. However, Gagliardi emphasizes that the quality of cotton varies by manufacturer, so always check the care tag for specific instructions.
Before washing colored cotton in hot water, Gagliardi recommends a quick colorfastness test. "It's a good idea to check an item with color for general colorfastness by handwashing it first with a small amount of laundry detergent, gradually increasing the water temperature to see if warmer water causes any dye to bleed off," she explains. Some garments stop losing dye after a few washes, while others never do, making like-color sorting essential.
Practical Tips for Hot Water Washing
Gagliardi also advises checking whether the item is 100% cotton or a blend. Many cotton items include polyester or spandex, which can still be washed in hot water (50°C/122°F) but may require a lower ironing temperature.
Air drying is another effective strategy. Gagliardi says air drying helps preserve colors, particularly on screen-printed t-shirts, and prevents the shrinkage that can occur in a hot dryer.
Understanding your washer's actual water temperature is crucial. "Depending on the location of your hot water heater and how much water your washer uses, your washer may finish filling with water before very much hot water is delivered to the washer, resulting in cooler wash temperatures than you think," Gagliardi notes. For top-loading machines, she suggests pausing the cycle mid-fill and using an instant-read thermometer to check the water temperature. If the hot setting is closer to warm, you may need to select a higher temperature for better results. Alternatively, if you have a laundry sink nearby, run the hot water line into a bucket until it's hot, then start the washer.
Ultimately, the experts agree that while hot water offers benefits like stain removal and bacteria elimination, it's not a one-size-fits-all solution. Careful attention to fabric type, care labels, and your appliance's behavior can help you make the right choice for your cotton laundry.
