Using Cold Water
Cold water also works better on protein stains like blood, milk and eggs, according to Ohio State University.
Using Hot Water
Hot water helps loosen dirt and works best for most stains and carpet types. Combine hot water with a carpet cleaning solution and you will clean your carpets without hiring a professional.
Bottom Line
Unless you’re cleaning a protein stain or have a cold water only extraction machine, use hot water to clean your carpets. According to the University of Missouri Extension, turn your hot water heater no hotter than 120 degrees Fahrenheit to keep you and your family safe.