What makes hot water better for cleaning than lukewarm or even cold water? Cleaning i.e dishes, surfaces, and even ourselves in the shower.


As far as I’m aware, the only benefits you get from cleaning with hot water come when it’s near boiling temperatures.

In: Chemistry

Hot water has more space and activity between molecules meaning it has more space and energy to dissolve dirt and grime.

In power washing, cold water may need additional chemicals to clean the same areas where hot water will easily clean with only the water

Heats things up. A lot of foods turn liquid when warmer, especially if there’s oil and fat involved. Sauces are like this too. Basically you’re getting it to melt off

When you’re washing anything – be it dishes, clothes, a body etc. – what you are doing is dissolving the stuff you want to get rid of in a solvent, which then runs down a drain into the sewer. Water is a good solvent for doing this, but in some applications other solvents are used as well (e.g. dry cleaning uses industrial chemicals).

Hot solvents dissolve things more effectively – think about sugar in hot coffee vs. cold. This is because hot liquid has more kinetic energy. It’s why iced coffee at a cafe is made hot and then poured over ice vs. being made cold from scratch – it’s much easier and quicker to dissolve things in a hot solvent, full stop, than having to agitate or stir the hell out of the liquid to assist the dissolving process.

Cold water has less dissolving power and is therefore less effective at cleaning things, because instead of blending with the water and running down the drain, stains remain on dishes and surfaces. If you’re using a cold liquid to clean things, you will need to make up for the lack of kinetic energy in the liquid by introducing kinetic energy externally – when washing clothes this comes in the form of a rotating drum, when washing dishes this comes in the form of friction via increased water pressure or scrubbing.