A pressure washer works by utilizing the power of water—often in combination with soaps and other cleaning chemicals—to remove hard-to-clean dirt, grease, stains, and other messes.

Even when using just water, pressure washers do a great job of cleaning dirt off any number of surfaces because water molecules have a slight electrical polarity (which means one end is positively charged and the other end is negatively charged), so they stick to whatever you are trying to clean. And the narrow, high-pressure water jet of hot or cold water that pressure washers deliver blasts away dirt and grime. But how can you know when to use hot water or cold water? What’s the difference, and does it matter?

Cold Water VS Hot Water

Cold Water Pressure Washers

If you are seeking a less expensive power washer, you’ll want to look for cold water ones. These are perfect for light to medium cleaning projects as well as jobs where hot water might cause damage to a surface. (Hot water, for example, can cause bare wood to swell, splinter, and split.) Think of cold water pressure washers as penetrative scrapers; they are perfect for cleaning siding and decks as well as boats, cars, and trucks.

Hot Water Pressure Washers

Any job that requires heavy duty cleaning or removal of oil or grease, on the other hand, will probably require a hot water pressure washer. These will do a better job of breaking up and removing oily and grimy dirt. Think about when you do dishes; hot water does a much better job of cleaning them. These are perfect for cleaning engines, construction equipment, oily driveways, and other situations where sanitation is a concern like in restaurant kitchens. Hot water power washers are also better for colder climates and weather as they will not freeze.

As a general rule, hot water will have better cleaning power than cold water. Cold water pressure washers, however, tend to be less expensive to buy and maintain. So, whether or not you chose to purchase a hot water or cold water pressure washer depends on your specific needs.