A pressure washer and a power washer both blast surfaces with high-pressure water. When people do draw a line between them, the line is heat: a power washer heats the water, and a pressure washer uses cold or unheated water.
In everyday American usage the two terms are often swapped, so a product listing or a bid may use either word for the same machine. This guide separates the two ideas so you can match the machine to the job, and flags the surfaces where heat does more harm than good.
- The one consistent difference is water temperature: power washing uses heated water, pressure washing uses cold or ambient water. Pressure itself is similar between the two, and depends on the machine you buy.
- Hot water pays off on grease, oil, gum and sticky buildup, such as loading docks, dumpster pads and parking areas. Cold water is the better and safer default for dirt, light mildew and general rinsing.
- Keep heat off softer or finished surfaces such as wood, siding and painted areas. Roofs, vehicles and windows call for a gentler soft-wash method rather than either machine at full pressure.
- A hot-water machine adds a burner or heater, fuel and a warm-up time. If you only need heat occasionally, a heater add-on for an existing washer is an alternative to buying a full hot-water unit.
What Is the Difference Between a Pressure Washer and a Power Washer?
The difference is water temperature. A power washer heats the water, while a pressure washer sprays it cold or at ambient temperature, and both use a pump to deliver the water at high pressure.
Two cleaning-service guides, from Durling Cleaning and Shack Shine, describe it the same way: both machines produce a powerful high-pressure stream, and the heating element is what sets a power washer apart. Shack Shine adds that how much pressure you get depends on the type of machine, since a household unit does not match an industrial one.
Because many sellers use the words loosely, check the spec sheet rather than the name. Look for the words hot water or cold water in the product title, and for a burner, boiler or heater. In our catalogue the machine type is stated in the title, for example the cold-water gas Pressure-Pro Eagle II E4040HG-20 and the hot-water gas Pressure-Pro Hot Shot 4012-10C.
How Do Pressure Washing and Power Washing Compare Side by Side?
Power washing wins on grease and sticky grime, and pressure washing wins on cost, simplicity and surface safety. The table below follows the comparison in the Durling Cleaning guide.
| Feature | Pressure washing | Power washing |
|---|---|---|
| Water temperature | Cold or unheated | Heated |
| Best for | Loose dirt, light mold, mildew | Grease, oil, sticky grime |
| Surface sensitivity | Suitable for hard surfaces | Can damage delicate materials |
| Typical use | Siding, decks, patios, general exterior cleaning | Commercial jobs, concrete, heavy stains |
| Extra equipment | Pump, hose, gun, wand, nozzle | All of that plus a burner, boiler or heater and its fuel |
For pressure range, Durling Cleaning says most pressure washers run between 1,300 and 3,000 PSI. Commercial machines can go higher, and our pressure washer PSI chart lists PSI and GPM by job.
When Is Hot Water (Power Washing) Worth It?
Hot water is worth it when the soil is oily or sticky and cold water alone leaves a shadow behind. Heat softens grease and loosens buildup, so the water has less to do mechanically.
- Grease and oil. Shack Shine says power washing is particularly good on grease stains on driveways and garage floors, and Durling Cleaning lists oil-stained garage floors and parking lots among its best uses.
- Sticky residue. Shack Shine notes that added heat also helps with things like chewing gum on sidewalks.
- Commercial concrete and large areas. Durling Cleaning calls power washing the better choice for large surfaces or grime that cold water cannot handle, such as grease-slick lots and warehouse exteriors.
- Graffiti. Durling Cleaning also lists graffiti removal as a power-washing job.
The cost of heat is real. A hot-water unit carries a burner or boiler, a fuel supply and a warm-up wait. Our pressure washer how-to notes that the boiler on a hot-water machine has its own start switch and about 5 minutes of warm-up before you clean. If you only need heat now and then, a diesel-fired heater made for an existing washer, such as the Pressure-Pro Hot Box HBS12V40, is an alternative to replacing the machine. Check the listing for flow and pressure ratings before pairing it with your pump.
When Is a Cold-Water Pressure Washer Enough?
Cold water is enough for loose dirt, dust, light mold and mildew, and routine exterior cleaning. It is also the safer choice on any surface that heat could harm.
- Everyday dirt and mildew. Durling Cleaning lists mold or mildew on siding, dirt on fences and decks, and post-winter driveway cleanup as cold-water jobs.
- Wood and siding. Durling Cleaning says to stay with pressure washing only on wood and siding, since hot water and high pressure can damage wood fibers.
- Concrete and brick. Durling Cleaning says both methods can work well. Shack Shine adds that pressure washing is less harsh on surfaces and suits masonry, brick and concrete.
- Vehicles, roofs and windows. Durling Cleaning advises avoiding high pressure on these and using soft washing, a gentler low-pressure method with specialized cleaning solutions.
Cold-water machines are also the simpler fleet choice. A cold-water electric unit like the Pressure-Pro Eagle EE2015G has no fuel or burner to maintain. For nozzle choices on any of these, see the pressure washer nozzle chart.
How Do You Choose Between Hot and Cold Water for Your Site?
Choose by the soil first, then by the surface. If the main problem is grease or oil on hard surfaces, hot water earns its cost. If it is dirt on mixed surfaces, start with cold.
| Job | Start with | Why |
|---|---|---|
| Grease on a loading dock or dumpster pad | Hot water | Heat helps break down grease and oil |
| Oil stains in a parking lot or garage | Hot water | Named as a best use by Durling Cleaning |
| General dirt on concrete walkways | Cold water | Enough for loose dirt and light mildew |
| Wood decks, fences and siding | Cold water only | Heat plus pressure can damage wood fibers |
| Roofs, vehicles, windows | Soft wash method | High pressure is not advised on these |
Most sites end up with a cold-water machine for volume work and either a hot-water unit or a heater add-on for the greasy areas. Browse both in the pressure washers collection, and if you want a rule of thumb for horsepower and flow, the best commercial pressure washer guide compares types.
How Do Hot Water, Degreaser and Wash Water Work Together?
Heat and a degreaser do different jobs on grease, and many crews use both on the worst spots. Whatever you use, the wash water has to be managed.
A degreaser applied through the soap tip breaks down the grease, and the rinse then carries it away. Our guide to pressure washer soap vs degreaser covers injectors and mixing, and how to get oil stains out of concrete walks through an oil-stain job.
Its label says it is ready to spray, mop or apply by pressure washer once mixed, and that it rinses residue-free with hot or cold water, so it works with either machine type. It contains no phosphates, petroleum solvents or VOCs. One 3.6 L jug makes about 720 L of working solution at 1:200.
- Keep wash water out of the storm drain. EPA stormwater guidance for vehicle and equipment washing advises keeping wash water out of the storm system (EPA stormwater BMP). Grease-laden hot water is no exception.
- Control wet floors. Where wet processes are used, OSHA requires drainage to be maintained and, to the extent feasible, dry standing places such as mats or platforms (OSHA 29 CFR 1910.22).
- Treat hot water as a hazard. Keep the spray away from skin, wear eye, hand and foot protection, and never aim the gun at people. Our how-to guide covers shutdown and safety in full.
Frequently Asked Questions
Is a power washer the same as a pressure washer?
They are similar but not identical. Both spray high-pressure water, but only a power washer heats it. In casual use the two words are often swapped, so check the product title for hot water or cold water.
Which is better for grease, a power washer or a pressure washer?
A power washer, because heated water works better on grease, oil and sticky buildup, according to the Durling Cleaning and Shack Shine guides. A cold-water machine paired with a degreaser is the other route, and our degreaser guide below covers how to apply it.
Can I use hot water on a wood deck?
No. Durling Cleaning says hot water and high pressure can damage wood fibers, so use cold-water pressure washing or soft washing on wood and painted finishes.
Does a power washer use more pressure than a pressure washer?
Not by definition. Shack Shine says both use similar amounts of pressure and that it depends on the machine, since a household unit is weaker than an industrial one.
Can I add hot water to a cold-water pressure washer?
Some heaters are sold for existing washers. The Pressure-Pro Hot Box listing states it is a diesel water heater made for an existing pressure washer, so check its flow and pressure ratings against your pump before buying.
Related Guides
- How to Use a Pressure Washer: 8 Steps for Gas, Electric and Hot Water
- Pressure Washer Soap vs Degreaser: What to Use and How to Apply It
- What Is a Good Pressure Washer PSI? A Commercial Job Chart With GPM
- Pressure Washer Nozzle Chart: Colors, Angles and Tip Sizes