Here you’ll be introduced to the 2 best hot water pressure washers for most people. One is a light-duty electric. The other is heavy-duty with a gasoline powered engine / pump and diesel burner.
Unless you’re a pro that gets paid to power wash don’t buy a hot water power washer.
Why? They’re just too expensive for residential-use. The most affordable one is $1,799 (on-sale). And that’s the 1,200 PSI machine down below.
But if money is no matter and you’re dead-set on a hot water unit then let’s take a look why hot water cleans more, better and quicker.
How Hot Water Pressure Washers Clean Better, Faster
Here’s the deal:
Answering why hot water cleans better than cold water is right up my alley… It’s a simple study in thermodynamics (heat and energy, including internal energy of a system) and kinetics (forces and motion) – both branches of physics. I studied mechanical engineering, which included a few thermo and kinetics courses… But who cares about the equations and fancy terms, let’s just talk about the gist of it:
Cold versus Hot Water
There’s 2 reasons why hot water cleans better than cold water: It has more energy to dislodge the dirt from the surface and it also attracts the dirt away from the surface better when hot. Hot water is a better boxer than cold water – it can easily surround and punch-out then carry away the dirt. Cold water is slower, and not very good at getting in close to Mr. Dirt Stain to land a finishing blow. And in physics terminology:
- The higher temperature means the water molecules are on average bouncing around faster – they have more kinetic energy. When introduced to a surface they will quickly bounce around dislodging any weaker molecules such as oil stains or dirt that is on the surface.
- The heat increases the internal attractive energy of the water, allowing it to have more attractive force on a microscopic level. Although this energy increase is much less prominent than the increased kinetic energy it still allows improved ability to “suck” away the stain/dirt molecules from the surface.
Soap versus No Soap
Going back to the hot water is a better boxer analogy… Soap would be like allowing the boxer to have a lasso (and he’s a hobbyist cowboy well trained at using it). With it, he quickly loops the rope around Mr. Dirt Stain pulling him in towards his lethal right hook. It’s game over. Dirt Stain has no chance.
Now that you’re starting to realize the benefits of hot water for cleaning, let’s take a look at what a hot water pressure washer is made up of:
Features That Matter
The burner supplies the heat. In the common hot water pressure washers it uses diesel fuel. Kerosene is also common. It has the ability to raise the temperature of the incoming water by 130F (55C). Some machines can even get you a 250F (120C) wet steam.
Burner Fuel Tank Size
Take note of the fuel tank size for the burner. It’s usually between 4 and 10 gallons. The bigger the tank the heavier the unit, but also the less often you’ll need to fill it up.
The heating coil is where the weight of a hot water pressure cleaner comes from. It’s made of schedule 80 pipe or tubing. You can see its mass in this picture. That’s all steel.
Gas or Electric
Trailer or Push Cart
The bigger the heating coil, burner, fuel tank and engine the bigger the cart frame needs to be… The biggest are often trailer mounted and are to be pulled from site-to-site by truck. Other come with frames and 4-wheels to push around. And some, like the electric Mini-brute below, just have 2 wheels.
Best Hot Water Pressure Washer For Most People
This is the most affordable hot water pressure cleaner available – it has light-duty pressure.
Even if you DIY’d your own machine with wholesale parts part-by-part (so no labour cost or profits to Simpson) you’d end up spending very close to what this machine costs.
I mean, just the burner and coil will run you $911… Then you’d need insulation, the stainless wrap, electrics, the actual pressure washer parts, the cart, assembly… All I’m trying to say is hot water units are expensive to buy because they are expensive to make.
The Mini-brute will give you 1,200 PSI, 2.3 GPM and a temperature rise of 100F (38C). And it plugs in to your household outlet with a 3-prong grounded plug.
Best Heavy-duty Hot Water Power Washer
Here’s a rather large heavy-duty machine, at 530 lbs and 44-inches tall, it needed to be on 4 wheels, have a hefty steel frame and thick pneumatic tires.
It can raise the temp of the incoming water by 140F (60C). And has a 6 gallon diesel fuel tank onboard to allow you to work extended periods with needing to refuel.
The Shark brand is owned by Karcher. It is also backed by a 7-year limited warranty on the pump, and a limited lifetime warranty on the chassis.