When Should You Use Hot vs Cold Water for Laundry?
Cold water works for most laundry and saves energy. Use hot water for heavily soiled items, towels, bedding, and when sanitizing is needed (illness, allergens). Use warm water for permanent press and synthetic fabrics. Cold water prevents shrinking and color bleeding, works well with modern detergents, and is gentler on fabrics. Always check care labels.
Key Takeaways
- Modern detergents are formulated to work effectively in cold water.
- Blood and protein stains should be treated with cold water first - hot water sets these stains.
- Some washing machines have a 'sanitize' cycle that heats water beyond the hot water heater setting.
Explanation
Modern detergents are formulated to work effectively in cold water. Enzymes and surfactants in today's detergents clean well at any temperature. Cold water (60-80°F) prevents shrinking, reduces color fading and bleeding, and is gentler on elastic and delicate fabrics. It also saves significant energy - water heating is 75-90% of laundry energy use.
Hot water (130°F+) is appropriate for heavily soiled work clothes, cloth diapers, towels and sheets for sanitizing, items exposed to illness, and allergen removal. Hot water helps dissolve oils, kill dust mites and bacteria, and works better on stubborn stains like grease. However, it can shrink natural fibers and fade colors.
Warm water (90-110°F) is a middle ground for permanent press items, synthetic fabrics, and moderately soiled clothes. It provides some sanitizing benefit without the shrinkage risk of hot water. Many 'colors' loads do well in warm water. Heavily stained items may need pre-treatment regardless of water temperature.
Switching from hot to cold water for laundry saves roughly $60-100 per year for an average household doing 300 loads annually. The Department of Energy estimates that heating water accounts for about 90% of the energy a washing machine uses per cycle. A hot water cycle costs approximately $0.50-0.68 in electricity or gas, while a cold water cycle costs about $0.04. Over the lifespan of a washing machine (10-13 years), the cumulative savings can exceed $800.
Specific stain types respond differently to water temperature, and using the wrong one can permanently set a stain. Blood, sweat, and other protein-based stains should always be treated with cold water first because heat denatures the proteins, bonding them to fabric fibers. Grease and oil stains respond best to hot water, which helps dissolve and lift the fatty molecules. Dye-based stains (wine, berries, grass) should be treated with cold water and a stain remover before washing. As a general rule, pre-treat first in cold water, then wash at the temperature appropriate for the fabric.
Things to Know
- Blood and protein stains should be treated with cold water first - hot water sets these stains.
- Some washing machines have a 'sanitize' cycle that heats water beyond the hot water heater setting.
- High-efficiency (HE) detergents are specifically designed for cold water use.
- Bed bug infestations require washing at 120°F or higher for at least 20 minutes to kill all life stages, making hot water essential in that situation.