Illustration for Hot-Water Pressure Washer Cost

One maker’s burners use 2.21 to 2.66 gallons an hour, about $14 to $16 an hour while firing at this month’s national diesel price.

The hot box plumbs onto your cold machine. Whether heat pays depends on how much of your work is grease, gum and oil, not on how cold it gets. It’s a common forum question. On a trade forum, an owner with a 4 GPM cold skid said commercial trash pads and stained patios had him eyeing a hot-water add-on. On Reddit, another washer asked whether he could just heat a 55-gallon tank instead.

What heat costs to buy

Option Example (dealer) Listed price Burner fuel use (maker spec)
Add-on hot box, 4 GPM, 12V diesel HBS12V40 (Sprayer Depot) $2,498 Not listed
Add-on hot box, 6 GPM, 12V diesel PP HBS12V60 (3R Sales & Service) $3,812 Not listed
Complete unit, 4 GPM, diesel-fired BE HW4013HG (Kleen-Rite) $5,065.06 2.21 gal/hr (BE)
Complete unit, 4 GPM, diesel-fired PowerJet PJO400412HGP (3R Sales & Service) $6,882 Not listed
Skid, 8 GPM, diesel-fired BE HW3024HG12V (3R Sales & Service) $12,136 2.66 gal/hr (BE)
Skid, 7.8 GPM, diesel-fired 3R HDS35081H6G (3R Sales & Service) $16,272 Not listed

Prices were checked October 9, 2026. Several units were listed as out of stock or pre-order, and dealer prices change often.

Can you just heat the tank?

Not well. On a hot-water machine, the pump pushes cold water through a heated coil. One maker says the coil brings it up to about 200°F before it leaves the wand. Heating the tank does the opposite. It sends hot water into the pump.

Pump makers cap that. One pump maker’s page lists a maximum temperature of 140°F for a 4 GPM direct-drive pump. Another’s spec sheet lists a maximum fluid temperature of 165°F for its 4 GPM triplex. So a heated tank tops out well below what a burner delivers. Washers on Reddit added two warnings. Seals don’t last long when a pump runs hot. And a hot inlet may need to be pressure-fed to avoid cavitation. Check your own pump’s sheet before you try anything.

Hot box or complete unit?

A hot box sits between the pump and the gun. Match its flow rating to your machine. One maker sells its 12V box for 5 to 6 GPM cold machines with a high-output charging system. The burner runs off that power. A Reddit commenter noted the other route: a 120V burner with a small generator.

The forum owner with the 4 GPM skid got blunt advice. If commercial work is where you’re headed, an 8 GPM hot machine may beat an add-on. On Reddit, a washer said piecing a setup together often costs more than buying a complete unit. Compare the table. A 4 GPM box at $2,498 is about half the price of a complete 4 GPM unit. That holds only if your cold machine is already a good match.

What it costs to run

The burner is the new fuel bill. Using the national on-highway diesel price of $6.199 a gallon for the week of October 5, 2026:

  • 4 GPM burner: 2.21 gal/hr × $6.199 = about $13.70 an hour.
  • 8 GPM burner: 2.66 gal/hr × $6.199 = about $16.49 an hour.
  • A four-hour dumpster-pad job on the 4 GPM unit: up to about $54.80 in burner fuel.

Those are ceilings. A burner cycles off when the water reaches temperature. Your engine fuel is extra, and so is upkeep. One owner on a trade forum describes replacing the burner nozzle and electrodes every year. Others on Reddit point to scale inside the coil when heat swings from warm to scalding. That calls for a coil descaler.

When heat is worth it

Heat earns its keep on grease, gum and oil. Restaurant dumpster pads are the usual reason. See what restaurants and storefronts pay. Gum is the other. Hot water is what most operators name first in our guide to gum removal on commercial sidewalks.

Cold weather is a weaker reason. In Anchorage, NOAA’s 1991 to 2020 normals put the average high at 28.9°F in November and 22.7°F in January. Heat at the wand won’t change the air temperature around the walk, so rinse water can still freeze on it. A hot unit may stretch your shoulder months, but treat a hard freeze as a no-wash day. Read washing a house in winter for the freezing risk.

Before you buy, count last season’s jobs that truly needed heat. If it’s a handful, renting or subcontracting may be cheaper for now. If it’s every week, add burner fuel per hour to those quotes. Our guide to bidding commercial jobs covers what to ask. For cold storage, see winterizing a pressure washer.

Burner safety

OSHA says carbon monoxide comes from incomplete burning of fuels such as kerosene, oil, propane and gasoline. It tells employers to provide ventilation and to bar gasoline engines in poorly ventilated areas. Never fire a burner in a closed garage, van or bay without the venting its manual requires. This is general information, not safety advice. Your machine’s manual comes first.

For how we check every number, see our methodology.

Sources

Based on 15 sources · How we price

Makers, dealers and agencies are cited for what their pages say. None endorses this site. Community threads are cited only for what operators asked and reported.