A comparison document fails in a quiet way. Nobody misreads a number. Each supplier simply fills in a different page: one publishes a steam temperature, another publishes a feature list, a third publishes the word efficient and nothing else. By the time the three offers sit side by side there is nothing left to compare. The fix is not more research. It is writing the rows first, then asking every offer to answer those rows.
For this machine the rows matter more than usual. The PowerDe HMW2 steam cleaner is not a box you park next to a drain and plug in. Its own listing says the 48 V battery is supplied by the customer, that the machine drives itself and can be stopped and driven at any time, and that it carries a 60 L clean water tank with it. Facts like those change what a fair comparison has to contain. The power chain becomes a line item. The route through your building becomes a measurement. The distance to a tap becomes part of the working day. What follows is what belongs in that document, using only the figures the product listing publishes, with the gaps marked as questions to be closed in writing rather than filled with assumptions.
Write your own task on the left side before you read a single specification
The left column of the comparison is not a machine. It is your work, written so that a stranger could price it. Which surfaces are in scope and which are explicitly out. What is on them, described by condition rather than by the word dirty: loose dry material that comes off with a brush; a fresh film that moves when it is warm; a baked-on layer that has been through heat cycles and behaves more like a coating than like soil. How many vehicles or square metres per shift, and how many of those fall inside the time you actually have once cooling, masking, drying and inspection are subtracted. What has to be true before the vehicle or the bay goes back into service.
The listing places this machine in indoor garages and in narrow spaces of outdoor parking lots. If your work sits inside that description, the comparison can proceed on published facts. If it does not, the first written question is whether the manufacturer treats your task as in scope, and the answer belongs in the document beside the row it affects. Without the left column, every specification sheet you read afterwards will look adequate. That is not a coincidence; it is how a comparison goes wrong at the lowest possible cost and the worst possible time.
Make the battery a line item, not a footnote
The working voltage row on the listing reads 48 V mobile battery, with the remark that batteries are customer provided. A separate listing for the same model is published with a battery included. That single difference is the most consequential row in the whole document, because it decides who owns the part of the machine that most often fails first. Whoever supplies the battery owns its selection, its charging regime, its degradation and its replacement, whether or not that was ever written down as a decision.
So the comparison needs these rows, and none of them are answered by the listing:
- Which offer is being priced: the machine without a battery, or the machine with one, and exactly what is in the crate.
- Battery make, model, chemistry and capacity in ampere-hours, and the voltage and connector the machine expects.
- Runtime per charge stated against a duty cycle like yours, not a laboratory figure, plus charge time and charger output.
- Whether opportunity charging between tasks is supported, and whether a spare battery can be swapped by your own staff.
- Who warrants the battery and for how long, and what the replacement costs and costs in lead time when it is done.
- Where the battery may be charged and stored, and what your building has to do to allow that.
A supplier who answers these with a part number and a charge curve has run this machine on a real shift. A supplier who answers that it runs all day has not, and that difference is worth more than any line in the specification table.
Put the machine's own geometry against your route, in your numbers
The listing publishes machine dimensions of 1275 mm long, 570 mm wide and 1185 mm high, with movement described as autonomous driving. Those three numbers are only useful once they are placed against numbers you measured with a tape in your own building. A machine that fits through the workshop door and cannot get down the basement ramp is a delivery problem nobody planned, and it is discovered on the day the crate arrives.
- The narrowest gate, aisle and doorway on the route, measured clear, including anything fixed that a driver would naturally steer around.
- Headroom along the route and at the parking point: sprinkler heads, ducts, cable trays, lift ceilings, door lintels.
- Ramp gradients, thresholds, expansion joints and drainage grilles, and how the surface behaves when it is wet rather than dry.
- The turning space at the working end, not only on the approach, since a machine that drives itself still needs somewhere to change direction.
- Where it will stand when idle and where it will be charged, and whether those places sit on the route or force the machine to be moved by hand.
Write your measurements in the row and ask each offer to confirm the machine passes them. Marketing words such as compact or nimble are not comparable; a clear width of 640 mm at the paint-mix room door is.
Read the water system as a working radius
The listing gives a 60 L clean water tank, a tap-water inlet with a 4-point internal-thread fitting, and a high-pressure water gun with nozzle as the cleaning method. Read correctly, those three lines describe a loop, not a capacity. The tank is the buffer between the machine and a tap; the fitting tells you whether your hose and your hydrant can actually talk to it; the gun tells you which mode carries water to the surface.
What the listing does not give is the rate at which any of it is consumed. Water use per hour and minutes of work per tank are not published, so they belong in the comparison as a written request and then as a measurement you take yourself on an ordinary shift. Until you have that number, the tank size cannot tell you whether one fill covers a bay or half a bay, and any schedule built on it is a guess.
- Distance from the working area to the nearest tap, and whether the machine can be fed continuously there or must be driven to refill.
- Whether the inlet thread matches what your site can supply, and what adapter is needed, by whom, before the first day.
- Where the wash water goes, and who owns the oil-interceptor question, which is a matter for your site and the local drainage authority rather than for the machine.
- Refill and restart written into the schedule as planned rows, since a water-shortage stop is a scheduling event and not a fault.
Compare what each mode does to your soil, not the mode names
Three cleaning modes are named on the listing: hot water, dry steam and wet steam. Mode names are not comparable between machines, because a name says nothing about what reaches the surface. What is comparable is the behaviour of your own soil under heat, dwell and wiping. Loose dry material wants removing, not heating; heat applied to it first simply produces mud to chase. A fresh film responds to warmth, a short dwell and a cloth. A built-up layer that has been cooked needs the surface brought up to temperature and held there, in two or three short passes with a wipe between them, and often a mechanical pass before any of that.
Here the comparison runs into a gap that has to be handled honestly. Other cleaning-machine listings on the same site publish a steam temperature and a steam pressure. This listing publishes neither, so the offers cannot be ranked by heat, and no figure from a neighbouring model should be borrowed to make the row look complete. Ask instead, in writing, for the temperature and pressure measured at the nozzle end with the wand and hose in the quoted configuration, because a long hose and a cold wand take energy out of the stream before it reaches your panel. Ask in the same letter which accessories are supplied, since the listing names the water gun and nothing else, and a brush, a pad or a lance extension changes what a mode is capable of more than the mode selector does.
List the protections by name and say plainly what they do not cover
The listing describes the machine as built with leakage protection, short-circuit protection, high-temperature protection, high-voltage protection, water-shortage protection and high-voltage explosion protection. Those are real design statements and they belong in the comparison by name, because a named protection can be asked about and an adjective cannot.
Then write the sentence that keeps the row honest. These protections act on the machine. They do not certify your wiring, do not notice that the floor is wet where people walk, do not train the person holding the wand, and do not decide where the wash water may go. A comparison that records six protections and none of the following rows will look complete and still produce an incident:
- A charging place, with the electrical work specified and checked by your own electrician against local requirements.
- Operator training and a named list of who is allowed to drive the machine, with a dated record.
- Personal protective equipment for the wand hand, and a rule for who may stand in the spray area.
- Traffic rules for a battery-driven machine moving through a building where people and vehicles already cross.
- Ventilation for steam used indoors, and a written handback rule for surfaces and floors that must be dry.
Keep the two listings apart, and price what is missing
The same model appears twice on the site, once without a battery and once with one, and the published specification table is the same on both pages. Treat them as two offers rather than as one machine with an option, and let the comparison be about what arrives, who owns the battery chain, and what each price includes. Then add one more row, titled simply not published on the listing, and put in it the battery capacity, runtime per charge, charge time and charger output, the steam temperature and pressure, the preheat time, the runtime per tank, the hose and wand lengths, the machine weight, and the service intervals and spare-part prices. Ask every supplier to answer that row in writing. A quotation that only reprints the listing has added nothing; a useful quotation closes the gaps the listing leaves open instead of re-printing them.
Before signing, read the quotation line by line against the page you compared. The model name and the battery variant must match the listing you read, since a quote naming only a model letter is not bound to either page. The published dimensions, tank volume and inlet fitting should be identical; a quotation carrying different numbers is describing a different machine, and that must be settled before anyone signs. Sending the row sheet together with your site conditions through the contact page turns three prices into three answers to one question, which is the entire point of writing the rows first.
Close the comparison with one day on your own vehicles
No document settles a question that a shift can answer, and no specification settles one about your soil, your aisles or your charging corner. Before the machine arrives, write the acceptance wording in the language your inspectors already use: under raking light no film remains on the agreed panel, the agreed white cloth passes along two marked edges, no water stands in sills, joints or recesses at handback. Tape half a panel and leave the other half as a reference. Photograph from a fixed point at the same angle, before and after.
Then run one day and time all of it: driving to the work, cleaning, refilling, charging, drying and inspection, because those are the hours you will actually pay for. Change one variable at a time, dwell first and distance second, so that the result can be attributed to something. Recheck the next morning, since flash rust, water spots and a decal edge lifting under softened adhesive all report late, after the crew has moved on. Send the record rather than the summary to the supplier; a supplier who can work with your timings will answer with intervals and parts, and one who cannot will answer with a catalogue.
The document that comes out of that day is the comparison. The one that comes out of a desk is a wish list with numbers copied into it. If the work you wrote in the left column turns out to need a different kind of mobile steam cleaning machine than the one you started reading about, that is also a result worth having a week early, and it is far cheaper than discovering it after delivery.
