View Full Version : Hot water Vs. Cold water Pressure washer...


Featherweight
03-08-2010, 10:08 PM
What advantages does a hot water pressure washers have over a cold water one? I have a 3500psi PW and my buddy has a hot water 2400 psi PW...HE thinks that his will out do mine when it comes to stripping...What do you all think?

stangfromhale
03-08-2010, 10:13 PM
Hot water does clean better. As far as stripping, I may be wrong, but it would seem the more pressure, the better.

akdiesel
03-08-2010, 10:24 PM
I personly don't see an advantage over cold pressure washers. Your cleaning ability is going to be the pressure the water is coming out at. The water comes out of the nozzle atomized, thus cooling the water droplets down faster.
Ever go to a car wash and feel their hot pressure washers. It is not that hot.

Joe B.
03-08-2010, 10:29 PM
3500 is a lot more than 2400 psi. I upgraded from a 2200 to a 2800 psi pressure washer when my old one died. No amount of heat would make up the difference for most applications. It should would be nice to run hot water on cold days.

Hot water does work better on grease or oil.

Abbott
03-08-2010, 10:36 PM
A hot water pressure washer does amazing things.

KingConstruction
03-08-2010, 10:37 PM
It all depends on what youre cleaning. We had a hot pressure washer and it was night and day difference on how much better the hot water and steam cleaned out engine bays and cleaned all the different oils off the shop floor and equipment. Nice thing about the hot, is that when you need it you have it and if you dont need the hot water then you can just turn the burner off

TONE
03-08-2010, 11:27 PM
Ever have dried paint or spackle on a tool?

Stick it under the cold water in the sink and nothing.

Then turn it to all hot and the stuff falls right off.

Same thing. Hot water pressure is far more effective even at lower psi's

BioHazard
03-09-2010, 12:45 AM
Doesn't matter what you're cleaning or what tool you're using, it almost always works better in warm/hot water.

Do you wash your dishes in cold water?
Do you wash your hands in cold water?
Do you wash your clothes in cold water?
Do you take cold showers?

Water is a solvent, believe it or not, and hot water is an even better solvent.

54FordPanel
03-09-2010, 04:23 AM
Hot water, hands down.

nissan_crawler
03-09-2010, 04:43 AM
I personly don't see an advantage over cold pressure washers. Your cleaning ability is going to be the pressure the water is coming out at. The water comes out of the nozzle atomized, thus cooling the water droplets down faster.
Ever go to a car wash and feel their hot pressure washers. It is not that hot.

That's because of safety bullshit. I dare you to stick your hand on the wand of the heated one we had on the farm There's a damn good reason it had a 2" heat guard around it. IIRC, the water was 160*

Your buddy is right, we had a 3,000 p.s.i. one, and had used it to wash an old pickup several times. I used the 2400 p.s.i. heated one, and it changed from blue to red to white to yellow, before I got it "washed". :spit:

The 3,000 p.s.i. one wouldn't get 1/3 of the grease/dirt that the heated one did.

sberry
03-09-2010, 08:20 AM
Washers are measured in cleaning units, pressure x gpm x temp is a simple version, hot cleans way better.

Kevin54
03-09-2010, 09:06 AM
I personly don't see an advantage over cold pressure washers. Your cleaning ability is going to be the pressure the water is coming out at. The water comes out of the nozzle atomized, thus cooling the water droplets down faster.
Ever go to a car wash and feel their hot pressure washers. It is not that hot.


There is a hell of a difference between a carwash warm water wand and a Steam Jennie diesel fired hot water system. They have special wands just so you don't burn your hands. Far superior cleaning than a standard pressure washer

akdiesel
03-09-2010, 11:58 AM
The car wash pressure washers are the only hot pressure washers I have delt with.
I don't see the extra $1000 or more over the standard gas pressure washer an expense needed to get most jobs done.
A little eblow grease (no pun intended) always got the job done for me.
I apologize for misleading anyone if the statements made are in fact true.

R6 Racer
03-09-2010, 12:08 PM
What about using a hot water line from your home?
I have both hot & cold water in my garage & I always use hot water threw my pressure washer (not a "heated" washer).
How do u think that would compare?

Steve

1Garageman
03-09-2010, 12:13 PM
Wonder how a hot water pressure washer would do on my driveway next year when it's covered with 6 inches of snow??? :lol_hitti
That could be interested:lol_hitti

lawfarm
03-09-2010, 01:02 PM
I'd say that they both would work better for different jobs under different circumstances.

If you're washing a car, you can't use 3,000 PSI directly on the paint, or you'll blow the paint off. So you have to run lower pressure with either washer. In that circumstance, the hot water will work better at cleaning than an equivalent pressure cold water pressure washer.

If you're degreasing something, the hot will work better.

If you're doing a job where temperature really doesn't help (e.g. washing a concrete sidewalk, or stripping paint from wood), then the heat is irrelevant.

I base this on my experience with our farm pressure washers (an old 220v electric cold water and a new Hotsy electric over diesel hot water), and my personal washers (gas powered cold water pressure washers).

It depends on what you're doing. For washing equipment and cars, I'd take the Hotsy any day. For washing the siding on my house, I'd rather drag my little gas jobby around.

R6--there were some discussions on that about 2 weeks ago. Consensus was that using even mildly heated (140 degree) water through a standard cold water washer was a ticket to a dead pump. That said, a regular water heater probably cannot keep up with a pressure washer very well.

Abbott
03-09-2010, 01:22 PM
If you're doing a job where temperature really doesn't help (e.g. washing a concrete sidewalk, or stripping paint from wood), then the heat is irrelevant.



I have cleaned a lot of sidewalks with cold and hot water pressure washers. The company I worked for owned a pressure washer and I had to often rent a hot water pressure washer to get the results needed for cleaning the concrete.

cyamaha2007
03-09-2010, 01:50 PM
we have a hotsy and it is amazing you can clean off salt snow road grime in nothing flat.

stltikn
03-09-2010, 02:21 PM
We also have a Hotsy. It's a hot water gas engine 4000 psi 3.5 gpm unit. We use it to clean everything. When cleaning the old Cats, the grime just melts away. Hot water really reduces the cleaning time. When you are cleaning a large machine it gets very tiring. I would recommend a turbo nozzle as that also reduces cleaning time. We also have a stepped plastic lock with a lanyard for the trigger that reduces fatigue. We have not found any soap solutions that are really more effective in removing old hardened grease and grime than just hot, 185 degree water. If you use a cold water unit, no matter what pressure, and then use a hot water unit, you will notice the difference.

sberry
03-09-2010, 02:29 PM
You can use a high pressure washer on cars, 3000#, that is at the nozzle, back off it a bit. Hot helps car washing, also in the winter time for blasting ice and snow off.
I have mine plumbed in, controls thru the wall, flip the switch for water and another for hot. Soap with the little garden sprayer when needed. Industrial Purple from HD for serious grease cleaning, not for use full strength on paint unless you want to strip it. There is also a milder stuff called pressure washer soap for painted surfaces.

Abbott
03-09-2010, 02:51 PM
If you use a cold water unit, no matter what pressure, and then use a hot water unit, you will notice the difference.

There it is.

Az Scooter
03-09-2010, 06:24 PM
I currently have five pressure washers. All of them hot water. Yes, it is what I do for a living, and a very nice living at that.
Cleaning units are just a marketing ploy. Gallons clean better than pressure, and there is actually a formula for relative effectiveness, which I don't have handy right now. It is far more complicated than the GPM x PSI formula.
Hot water does clean far better than cold water, in any situation. I would be willing to bet that no one on here cleans their dishes with cold water. There is a reason for it, and it is best illustrated by grease and oil. When molecules heat up, they start moving around. When they start moving around, they lose their electrostatic bond, and so become dislodged more easily. They same process happens with soaps, and detergents. It is accelerated by heat.
As for 2400 PSI hot working better than 3000 PSI cold, the hot will win every time, given that they have the same GPM. If you are just removing dirt, like mud from a surface, pressure will get you no where. I would rather have a fire hose to take care of it. Last I checked, a fire hose may put out 300 GPM, at 60 PSI. So the question is, using the cleaning units formula, to clear out dirt and debris, would you rather have the fire hose at 18000 cleaning units, or the pressure washer at 18000 cleaning units?

Sorry, I was rambling. The long and short of it is, the hot water will always clean better.

KM1013
03-09-2010, 08:06 PM
I'll jump on the "hot" band wagon. Having used a Karcher day in and day out for almost three years hot is the way to go.

wreckercologist
03-09-2010, 08:56 PM
The one we use at work is a Alkoda? Minkoda? I forget exactly what the brand is, but it's diesel fired and 2800psi. It works much better with the heat on.

Our painter uses it quite a bit to remove old paint:spit:

Works like a champ on concrete floors too.

I'd like to have one like it......too bad they're a couple grand new.

Abbott
03-09-2010, 10:20 PM
Yeah, I have a $300.00 cold water unit here at the house. It sure beats the heck out of nothing. A hot water rig is to expensive for me and they are pretty big to store.

BioHazard
03-10-2010, 06:11 AM
That's because of safety bullshit. I dare you to stick your hand on the wand of the heated one we had on the farm There's a damn good reason it had a 2" heat guard around it. IIRC, the water was 160*
Hell, even cold water at 2400 PSI will peel your skin off...I have the scar to prove it!

What about using a hot water line from your home?

I asked about this recently and the consensus was that you'll ruin most cold water units by doing that. As far as I understand, commercial hot pressure washers heat the water AFTER it comes out of the pump - so the pump doesn't get hot! It seems like a lot of the diesel type run at around 200 degrees also, so that's a lot hotter than your water heater.

Northern tool makes a diesel powered heater add on for "any" pressure washer, I can't remember how much it is now.

Az Scooter
03-10-2010, 02:41 PM
Consensus is wrong. The packing and seals in most pressure washers are designed to handle up to 140 degree water. Most people have their hot water heater set at 125. There may be some exceptions, but in all the years I have been dealing with pressure washers, I have not found any.