Three-Year Total Cost: A Worked Model for Dry Ice vs Pressure Washing

Most cleaning-method comparisons are nozzle-to-nozzle: this one's $X per hour, that one's $Y per hour, the cheaper number wins. Anyone who has actually run a maintenance budget for three years knows the per-hour rate is the smallest line. The fight is everywhere else — water and chemical, sensor replacement, downtime cost, corrosion-driven part replacement, labor for tear-down and re-assembly, and the cost of the cleaning slot you could not fit into the schedule so the equipment ran dirty for another quarter.

What follows is a worked model, not a customer result. Every figure below is a stated assumption chosen to show the shape of the arithmetic. None of it is a measured outcome from a Summit Cryo job, and you should not treat it as a forecast. Substitute your own invoice history for each placeholder — the point of the exercise is the line items you are currently leaving out, not the totals we picked.

Model A — fleet shop, 22 Class 8 tractors

Stated assumptions: 22 tractors, northern salt climate, quarterly steam and pressure wash at an in-house bay, $180 per truck per session including chemical and labor. That puts the visible wash spend at roughly $15,840 a year. This is the only line most controllers see.

The lines that usually sit in other cost centres, with assumed rates you should replace:

• Sensor and harness replacement tied to water and salt intrusion — assume 3.1 ABS or wheel-speed replacements per truck per year at $340 installed. Across 22 trucks that is about $23,200 a year.
• DEF-line and 7-pin connector replacement from corrosion — assume 1.4 per truck per year at $185. About $5,700 a year.
• Decal replacement from high-pressure edge lift — assume one unit-side per truck every 18 months at $420. About $6,160 a year.
• Bay tie-up — assume 3.5 hours out of service per truck per wash including dry-down, at $58 per hour of revenue contribution. About $14,300 a year.

Under those assumptions the modelled annual cost is roughly $65,200, or about $195,600 over 36 months — against a wash invoice of $15,840.

Now model the alternative with the same discipline. Assume a monthly dry ice route priced at $2,400 per visit, or $28,800 a year. To finish the model you must assume a reduction in each of the corrosion and downtime lines. Any reduction you assume is an assumption, not a measurement: dry ice adds no process water and no chemical, which is the mechanism people expect to drive the difference, but the size of that difference at your site is unknown until you have your own before-and-after invoice history. If you assume sensor replacements fall by half, connector replacements fall proportionally, decal damage goes to zero, and bay tie-up drops to one hour per truck per visit, the model lands near $42,700 a year.

That is the whole exercise: a higher cleaning line and a lower budget line, contingent entirely on assumptions you have to validate yourself. If your corrosion and downtime lines are small, the model will not close — and it should not.

Model B — single bake line, weekly hood and conveyor cleaning

Stated assumptions: weekly wet wash with caustic foam at $340 per session including chemical, labor, and the dry-down lockout window. Visible annual spend: about $17,680.

Assumed adjacent lines:

• Belt life — assume a stainless conveyor band replaced at 2.5 years against a manufacturer-rated 5, at $9,200. Amortized, about $1,840 a year of avoidable spend.
• Bearing housings — assume 4.2 replacements a year at $185 from caustic intrusion. About $780.
• Lost production at restart — assume 18 weeks a year where a same-day restart costs 1.5 hours at $640 per hour of contribution. About $17,280.
• Wash-water disposal and stormwater BMP compliance — assume $2,100 a year.
• Burner manifold pinhole corrosion attributed to caustic carry-up — assume $1,540 a year amortized.

Modelled annual total: roughly $41,200. The wash invoice is 43 percent of it. If your own numbers put the invoice at 90 percent of the total, the method change has very little to work with and you should stay where you are.

For the alternative, assume a weekly dry ice visit at $480, or $24,960 a year, and hold every other line at whatever reduction your own history supports. Note what genuinely does go to zero rather than merely falling: there is no wash water, so wash-water disposal and BMP spend for that step goes away, and there is no dry-down cycle, so restart delay attributable to drying goes away. Belt and bearing life are corrosion assumptions, and we will not put a number on them for your plant.

What the model cannot tell you

Dry ice blasting is mechanical soil removal. It does not sanitise or disinfect, and it does not replace a sanitizer step or satisfy any audit scheme — whether it fits inside your SSOP or HACCP plan is your QA team's determination. Substrate suitability, including paint, decals, seals, wiring and sensors, is confirmed with a test patch before a program is scheduled. Electrical equipment is cleaned de-energised under your own lockout/tagout. CO₂ displaces oxygen, so confined and low-airflow spaces require ventilation and CO₂ monitoring, plus PPE and an agreed plan for containing and collecting the dislodged contaminant. Hazardous materials — lead, asbestos, silica, PCBs, biohazard — are outside our scope without a licensed abatement contractor engaged.

Where pressure washing still wins

We are not the right answer for every job. Pressure washing wins clearly on:

• Concrete pads, parking lots, sidewalks, and exterior building wash. No electronics, no corrosion penalty, water is cheap, and pressure-wash crews charge a fraction of what we do per square foot.
• Vehicle exterior body washes where the goal is cosmetic and there is nothing sensitive under the panel.
• Heavy mud and aggregate removal from construction equipment, where the volume of material to displace makes water the right tool. Dry ice can finish what pressure washing started, but water is faster on the gross-soil pass.
• Anywhere a wash bay with floor drains, hot water, and existing chemical inventory is already paid for and the corrosion math does not matter — outdoor yard equipment, hand tools, low-spec storage racks.

How to run the comparison on your own budget

Pull these numbers from your last 36 months, not from a vendor's slide deck — including ours:

• Cleaning vendor invoices (the easy one).
• Sensor, harness, and connector replacement spend tagged to corrosion or water intrusion.
• Equipment replacement on items whose manufacturer-rated life exceeded your actual replacement interval.
• Production or revenue lost to cleaning windows, including dry-down and re-assembly.
• Wash-water disposal, BMP, and stormwater compliance spend.
• Insurance or environmental costs tied to runoff.
• Labor for the maintenance crew doing tear-down and re-assembly around the cleaning slot.

If those lines add up to more than your cleaning invoice, you have a TCO question worth asking. If they do not, pressure washing is probably fine and we will tell you so on the walk.