The hand work inside an interior clean
Split an interior into jobs before comparing anything. Five hand jobs carry most of the time. First, brushing and agitating, which turns bonded soil into loose soil. Second, wiping with a cloth, the largest single line in most interiors. Third, repeating that wipe, because a first pass often only moves the soil. Fourth, extraction or drying, which decides whether the vehicle can be handed back on time. Fifth, the containment work around all of it: removing mats, masking trim and keeping hoses out of door seals. Every method below either removes some of those jobs or moves them somewhere else.
Interior objects decide the answer surface by surface: door cards and armrests, the console and dashboard plastic, seat tracks, stitching, upholstery, carpet, headliner, boot floor, seat belts and the inside face of the glass. A method that behaves well on a hard door card can fail on a headliner, so a comparison that averages the whole interior into one score tells an operator nothing they can use.
What steam actually changes in the workflow
Heat releases bonded grease and skin oil from a surface, which is why a short dwell in front of the nozzle replaces part of the brushing and most of the second wipe. The powerde.net cleaning catalogue describes machines that switch between dry steam, which carries heat with little free water, and wet steam or hot water, which carries more water to lift heavier soil. That switching option lets one operator use dry steam on a headliner and hot water on a carpet. Check that the modes are listed on the page of the exact variant being quoted, rather than assuming them from the product range.
Where a catalogue page lists a vacuum function alongside the steam modes, it removes a separate vacuum-and-wipe pass on fabric and seat tracks. That row is not printed on every page in the range, so read the page of the exact variant. Steam without extraction is the failure mode to avoid: fabric left damp gives tide marks, needs a drying window, and pushes the hand work into the handover stage instead of removing it.
Alternative one: the cold-water hose and brush
This is the cheapest option to buy and the most expensive to run per vehicle inside a building. There is no heat, so agitation and wiping carry everything; a bonded deposit on a console needs cloth passes until it lifts. On a hard surface that can be soaked, the water drains away. On trim, seat foam and a headliner, the water has to be removed by hand before the vehicle leaves, which is the hand work the method was supposed to avoid.
Water volume, drainage and drying space are the costs an operator does not see on the invoice. The PowerDe catalogue places its mobile machines in indoor garages and narrow outdoor parking spaces. In exactly that setting a hose leaves a wet floor. A wet floor needs a wet-floor sign and a drying lane, and a drying lane takes space the bay does not have. For an interior, that is usually a losing trade.
Alternative two: a cold or heated pressure washer
Pressure does the work that heat would otherwise do, and it does it fast on an exterior. On an interior, pressure is a problem rather than a benefit. A jet drives water into seat-track mechanisms, door-card edges, handle recesses, stitching and any loose or unsealed trim, and it drives soil deeper into foam rather than out of it. Heated water improves the result on a hard surface and keeps the drying window short, but it does not change what the jet is doing at a seal.
For most interiors the honest comparison is narrower than it looks. Pressure wins where rinsing is possible and drying space exists, which means the exterior and the engine bay. Heat wins where the surface has to stay close to dry, which means the interior. Many operators end up with both, and the decision is which one carries which part of the job.
Alternative three: solvents, foams and trigger sprays
A solvent or a foam does a real job on a localised deposit, and it needs no machine at all. What it adds is a chemical inventory, a dwell that has to be watched, a residue that has to be rinsed or wiped off, and a disposal question at the end of the week. On upholstery a foam that dries into a powder has to be vacuumed out completely, or the fabric looks clean and then re-soils quickly. On a forecourt or in a leased bay, storage and disposal rules are the buyer's problem, not the supplier's.
If the reason for choosing chemicals is the purchase price, compare the price the operator actually pays over a year. Count the cans consumed per vehicle, gloves and ventilation, the residue wipe a solvent always leaves behind, and whatever the site has to pay to dispose of the used product. Steam brings its own running costs, which are power, water, consumables and planned servicing. Those are easier to count because they arrive on invoices the business already receives.
Alternative four: a vacuum and microfibre cloth
For a light refresh, a vacuum and a cloth is the right answer and nothing should displace it. Loose soil is loose, and suction removes it with no dwell, no heat and no moisture. The limit is bonded soil: grease on a door card, oil on a steering wheel, a drink ring in a carpet. A cloth on a bonded deposit spreads it, then the operator wipes again, and the second and third passes on those small areas are where the minutes go.
So the fair question is not "steam or vacuum". It is which jobs the vacuum already handles well and which ones it never will. The vacuum keeps loose soil. A heat-based method takes the bonded soil. That split is usually where the reduction in hand time comes from. On machines whose pages list extraction as well as steam, the two stages collapse into one pass.
Alternative five: contracted detail crews
Outsourcing removes the machine purchase entirely and moves the labour cost onto a per-vehicle price that is easy to compare with the in-house figure. It also gives up control of scheduling, of what is inspected before handover, and of whether the same method is used on a customer's headliner as on a fleet van. For an operator with an unpredictable flow of work, that trade can still be sensible; it is the option to keep in the table rather than assume away.
How to settle it: a bounded side-by-side trial
Choose two vehicles of the same type with a similar level of soiling. Clean one with the method the business already uses and one with steam. Agree the pass line before starting, so nobody argues about it afterwards: what counts as clean on the carpet, on the stitching and on the console, and who judges it. Then record four numbers per vehicle. All four are yours, none of them a supplier's.
- Hands-on minutes per vehicle, timed from the first movement to handover.
- Wipe passes per surface that needed a second or third pass.
- Drying or waiting minutes before the vehicle could be handed back.
- Return visits and re-cleans caused by damp fabric, tide marks or a smell.
Run the same pair again the following week before drawing a conclusion. Two vehicles prove nothing on their own, and the first run is always slower than the second because nobody knows the dwell yet. Keep the sheet with the purchase file: it is the document that shows what the method did in this bay, not in a demonstration.
What to ask the supplier, in writing
Send the same list to every bidder and read the answers side by side. A comparison that only one supplier answered in prose is not a comparison. Ask what steam temperature and supply pressure the quoted unit delivers, and whether those values are at the generator or at the nozzle. Ask which of dry steam, wet steam and hot water are available on that exact variant, and whether extraction is offered with it. Ask what working supply the unit needs, whether a battery or mains supply is required, what water it expects from the tap, and what a service visit costs and covers.
Two distinctions decide whether a spec sheet means anything at all. A temperature published on a page is usually a generator value, not the temperature the operator's nozzle delivers at the surface. And tank volume is not working time, because duty cycle, water feed and the operator's dwell decide how long a machine can run. A written answer that keeps those two separate is worth more than any brochure figure. Where a duty does not fit a catalogue configuration, customized steam cleaning equipment is the route PowerDe describes for adapting a machine to a real site.
What stays manual whatever you choose
No method removes the work that requires a hand and an eye. Seams, stitching, seat belts, the inside of a glovebox, the underside of a seat and the boot lip need attention whatever the machine. Loose or unsealed trim has to be found and fixed rather than sprayed at. Electrical components, airbag covers and any opening that takes water belong outside the spray zone on every method, including the gentlest one. Any comparison that promises to eliminate those jobs is selling something the operator will do by hand anyway.
Where steam sits in the range
The PowerDe catalogue covers mobile and fixed cleaning machines. One commercial steam cleaner is described for indoor garages and narrow outdoor parking spaces. A fixed steam cleaning machine is listed for tasks such as vehicle exterior work at fuelling and parking sites, engine-compartment cleaning, and interior vacuuming and disinfection. Those are the applications the pages themselves name. Treat them as the starting point of an enquiry rather than as a promise about your vehicles. Which machine, and which method, fits a particular interior is settled by the trial described above and by a supplier who answers the questions in writing.
Judged that way, steam usually wins the comparison on interior hand time, because it replaces agitation and repeat wiping with heat. It loses the comparison on nothing except the discipline of using the right mode and letting the surface dry. Operators who keep the trial sheet and the written answers can say exactly which hand jobs went away in their own bay, and which ones they are still paying for by hand.
