The machines in question are the ride-along, mobile active-water pattern sold as PowerDe PWD02, PWD01 and HMW2 - driving style steam cleaner units, catalogued both with and without a battery, and placed by their own pages in indoor garages and tight outdoor parking. For that class the operating bill is not one number. It is a small set of charges that move together, and the set shifts when the machine works at a different point along the line from the cramped bay to the open yard. A facility that prices the family this way, job by job and setting by setting, gets a defensible figure. A facility that takes a single per-shift average gets a number that fits nothing.
Settle what is being counted before any figure is gathered
Three questions decide which costs belong in the evaluation, and they have to be answered on paper before a spreadsheet is opened. Is the object one machine, or several in the same class bought for different corners of the site? Is the charge being judged the purchase price, the cost of a completed task, or the cost of keeping that task available during the hours the site actually needs it? And is the comparison being made against another machine in the family, against a fixed arrangement plumbed to one point, or against the hand method in use today? Each answer changes the boundary of the ledger. Pricing a single unit's energy consumption answers none of these; pricing a bay's wash under a chosen arrangement answers all three.
This step sounds clerical and is where most evaluations go wrong. A figure gathered under the wrong boundary is still a number, so nobody challenges it later, and a decision gets made on costs that were never the site's costs.
Treat the driving-style line as one family with two variant decisions
The pages for PWD02, PWD01 and HMW2 describe one working pattern: a mobile active-water machine that puts out dry steam, wet steam or a hot-water flush from the same unit, listed for tight garages and outdoor parking, catalogued with a battery on one page and without one on another. Several of those pages also list safeguards - against earth leakage, against short circuit, against excessive temperature, against high voltage, and against running the heater dry. That common description is the useful starting point for costing, because the same measurement routine applies across all three and the real differences can then be isolated instead of assumed.
Two decisions then separate the units. Which model the site is actually quoting, and whether that model is the battery-carrying page or the battery-free page. The published material for these machines does not give a flow rate, a steam temperature, a pressure, a heater rating, a tank volume, a battery capacity or a working period, so any evaluation for this class has to rest on what the site can measure itself and on written answers from the supplier, not on a comparison of figures nobody has published.
Charge the mode, not the machine
Heat is bought through the mode selected for the job, so a machine-level average hides the real driver of the bill. Dry steam is the low-water setting: most of what is paid for is heat, with little free water falling to the floor, which keeps disposal, cleanup and drying time low. Wetter settings and the hot-water pass release more water, and that water has to end somewhere - a drain route, a contained area, a mop-up step that someone performs and someone supervises. A task done in hot water therefore costs more than the energy used to heat it, and the difference is a site charge, not a machine specification.
The practical consequence is that any cost figure for this family is meaningless unless the mode is recorded with it. Two shifts of the same machine on the same equipment, one run dry and one run in hot water, produce two bills and two sets of downstream work. Comparing them is how a facility finds out whether the soil actually needs the wetter mode or whether the habit, not the deposit, is what is being paid for.
Measure what the site controls, and ask for what it cannot
The charges a facility can settle itself: the number of water refills per shift, logged as containers rather than litres and converted only once the fill pattern is understood; the electrical energy entering the position the machine is worked from, read with a plug-in meter over a normal week rather than calculated from a rating; the walking and repositioning distance between the working supply and the far bay, timed on foot on the actual surface; the count of tasks completed per shift; and the time taken per unit of area on the site's own panels, measured against the acceptance line agreed beforehand.
The charges only the supplier can settle, and which must be requested in writing before any purchase is agreed: the consumable parts that wear and their replacement interval, quoted against task count rather than calendar time; which protective functions the quoted configuration carries; the warranty terms and what voids them; service response and parts availability; and whether an accessory, a filling arrangement or a charging arrangement is supplied with the quoted unit or specified separately. A written answer turns an assumption into a line item. A verbal answer does not.
Price the availability window, because that is where these machines earn
A machine parked outside a bay nobody can use is not cheap. The published position of these units is the constrained setting - an indoor garage or a narrow parking space - and in that setting the value of a mobile driving-style machine is that it reaches the task inside the hours the site is open to traffic, to vehicles, to inspection, or to the next shift. The evaluation should therefore record the window the wash must fit into, then test whether the machine, in the configuration quoted, fits it: how far the working supply reaches, how many repositionings a route needs, whether a battery-carrying page or a battery-free page changes the route at all, and what happens when that window shuts while a task is still open.
This is also where the comparison against a fixed arrangement becomes real rather than theoretical. A plumbed-in installation pays for plumbing once and cannot follow the work. A mobile unit buys freedom to follow it, and pays for that freedom in walking distance, in repositioning, and in the site's charging rules if the quoted unit carries a battery. Whichever arrangement is cheaper depends entirely on how scattered the site's tasks are, which is a fact the site can measure and a supplier cannot.
Log water, power and consumables as they are actually consumed
Consumables fail on task count, not on dates. Nozzles wear, and a worn nozzle spends extra water and extra minutes before a surface reads as finished, so a worn part shows up as a labour charge long before it shows up as a spare. A written consumables list, a replacement trigger an operator can act on, and stock held for the parts that actually fail are cheaper than a shift run on a part past its life. The same logging discipline covers water and energy: read the consumables at the point of use, over a full week that contains the site's busy days, and never extrapolate from a favourable afternoon.
Run-off belongs in this ledger too. Where wetter modes are used, the water leaves the machine carrying the soil with it, and the site pays to contain, route and dispose of it. If the wash is happening in a garage or a parking area that drains somewhere specific, that constraint decides which modes are usable at all, and it should be settled before the machine is chosen rather than discovered after delivery.
Do not separate labour from induction and hand-off
Labour in this class of work is three charges, not one. The minutes spent on the surface. The induction needed so a new operator works the mode the site has chosen rather than the one they prefer, which for a family of similarly described units sold on several pages is a real risk: staff assume that what they know about one page transfers to the next. And the hand-off cost, the difference in output between an experienced operator and a new one on the same machine, which is measurable on the site's own panels and usually larger than any difference between models.
Any evaluation that leaves hand-off out overstates the machine and understates the training. Any evaluation that counts only the minutes on the surface will recommend the wrong machine, because a unit that is slower on the panel and faster to reach across a scattered site is often the cheaper one by the end of the week.
Run a bounded trial that answers every open line
A trial earns its cost only when it is bounded: fixed area, the site's real soil, a named machine in a named variant configuration, the acceptance line agreed before anyone starts, and a stop condition. Record against each line in the ledger - water containers, energy read at the position, repositionings, minutes on the surface, run-off handling, any protection trip, and whether the task closed inside the availability window. Then hold the trial record against the supplier's written answers and note where they disagree, because a disagreement between a measured figure and a promised one is worth more than either figure alone and is the most useful thing a trial produces.
The questions to put in writing at this stage are few: the figures this class of machine does not publish; the difference between the battery-carrying and battery-free configuration for the model being quoted; which protective functions the quoted unit carries; the consumables and their interval; and what is included on delivery. A site that asks these before ordering has priced the decision. One that asks them afterwards has priced the risk.
Where a custom arrangement changes the arithmetic
Some sites fall outside the published setting. A wash that must happen away from any garage or parking bay, a supply that cannot be reached, or a duty that a mobile unit carries awkwardly all point the evaluation toward a customized steam cleaning equipment arrangement rather than a catalogue choice, and the cost question then shifts to engineering scope, installation, and the work the site stops doing while that is in place.
The same shift applies when the decision rests on performance the site cannot see for itself. Independent steam cleaning equipment testing moves a claim from a supplier statement into a report both parties can hold to, which changes the cost of being wrong - and on a family of machines whose published pages carry no flow, temperature, pressure or runtime figures, the cost of being wrong is the largest single item on the sheet.
