A fixed steam cleaner and a mobile steam cleaner can look nearly identical on a shortlist. Both produce high-temperature steam, both list the same categories of electrical and thermal protection, and both sit in the same product category on a supplier's website. The difference between them is not the steam. It is where the power, water and drainage come from, and how the cleaning work reaches the machine. This article compares the two form factors using two published product pages from PowerDe, the fixed fixed steam cleaning machine HW02 and the driving-style PowerDe HMW2 steam cleaner, so every figure quoted below comes from a specification table rather than from generalisations.
What actually differs between the two designs
A fixed machine is installed at one point. The HW02 runs on a 220 V supply with 6 kW of heating power, carries an 80 L SUS304 tank, and connects to a tap water inlet through a half-inch internal-thread fitting. Because the tank is fed from the mains supply, the machine does not depend on someone carrying water to it, and the vehicles come to the machine. The HW02 page documents its use for vehicle exterior cleaning at gas stations and parking lots, interior vacuuming and disinfection, and engine-compartment cleaning.
A mobile machine reverses that arrangement. The HMW2 carries a 60 L clean water tank, runs on a 48 V battery that the customer supplies, and drives itself; the product page describes it as a driving-style device that can be stopped and driven at any time, intended for indoor garages and narrow outdoor parking spaces. The machine goes to the vehicles. In short, the fixed machine trades a one-time installation for a long, stable work cycle at one location. The mobile machine trades the installation for two routines that stay with you: refilling water and charging batteries.
| Comparison point | HW02 (fixed) | HMW2 (mobile) |
|---|---|---|
| How the work is reached | Installed at one wash position; vehicles come to it | Autonomous driving; the machine goes to the vehicles |
| Power source | 220 V supply, 6 kW heating | 48 V customer-provided battery, 4.5 kW PTC semiconductor heating |
| Water | 80 L SUS304 tank fed by tap water inlet (1/2-inch internal-thread fitting) | 60 L clean water tank, refilled from a tap water hose (4-point internal-thread fitting) |
| Published steam figures | 160 °C steam temperature, 0.8 MPa vapour pressure | Steam temperature and pressure are not published on the page; request them in writing |
| Cleaning modes | Dry steam, wet steam, with vacuum cleaner | Hot water, dry steam, wet steam; high-pressure water gun with nozzle |
| Machine size | 1200 × 800 × 1200 mm including handles | 1275 × 570 × 1185 mm, narrow body for tight spaces |
| What the buyer must provide | A dedicated 220 V circuit checked by an electrician, water and drainage at the point, a permanent position | Batteries, charger and storage; a refill and drainage routine within reach |
Compare these seven points, in this order
1. Where the work actually happens. Write down where vehicles are cleaned today and where they would be cleaned tomorrow. If the work happens in one bay, one position can be built to serve it. If vehicles are parked across a yard, a street frontage or several sites, a fixed machine will spend its life pulling hoses across the lot, and a mobile steam cleaning machine will save that walking and hose handling every day.
2. Utilities at the point versus utilities on board. The fixed machine needs three things at one spot: a dedicated 220 V circuit, a water connection, and a drainage path. The mobile machine needs none of those at the wash position, but it needs a charging place with a normal power outlet and a water point within reach of the tank. Walk your site and count how far the nearest water point is from where you would actually clean. If refilling means dragging a hose a long distance several times a day, the mobile machine is simply moving your problem, not removing it.
3. Work cycle and refill routine. The HW02's 80 L tank is fed from the tap supply, so at an installed point the machine can run through a long working period without a manual refill. The HMW2's 60 L tank is a working reservoir you empty and refill on a cycle you will have to measure. Before ordering, ask the supplier how many vehicle cleans a full tank supports in their testing, and then verify that number on your own vehicles during a trial.
4. Published performance figures. The HW02 page states a 160 °C steam temperature and 0.8 MPa vapour pressure. The HMW2 page states 4.5 kW of PTC semiconductor heating but does not publish a steam temperature or pressure. Do not assume the two machines deliver the same steam duty from similar-looking brochures. Ask for the mobile model's steam temperature and pressure in writing, and compare like with like.
5. Modes and attachments. The fixed HW02 switches between dry and wet steam and is offered with a vacuum cleaner, which suits the interior vacuuming and disinfection work its page describes. The mobile HMW2 adds a hot water mode and a high-pressure water gun, which is useful for loosening fresh road soil before steam work. Match the mode list to your soiling: fresh mud and salt respond well to hot water and a water gun; aged grease and oil films are where high-temperature steam earns its keep.
6. Size, doors and placement. The HW02 measures 1200 × 800 × 1200 mm including handles and needs a permanent position plus a delivery route to it. The HMW2 measures 1275 × 570 × 1185 mm; its 570 mm width is what lets it work in narrow garages and parking spaces. Measure doors, aisles and turning areas for either choice. A fixed machine that cannot be delivered through the door is not fixed; a mobile machine that cannot pass the gate is not mobile.
7. Protection features and what they do not cover. Both product pages list leakage, short-circuit, high-temperature, high-voltage, water-shortage and high-voltage explosion protection. These protect the machine. They do not size your wiring: a qualified electrician still has to confirm the dedicated 220 V circuit for the fixed unit. And on the mobile unit the battery is customer-provided, which puts the battery, charger, cables and storage outside the machine's own protection list. Budget for them and train your team on them.
Choose the fixed machine when
- You have one dedicated wash position and predictable daily volume at that position.
- Power, water and drainage are available or can be installed at one point at a reasonable cost.
- The work includes interior vacuuming and disinfection, where the fixed unit's vacuum option is used on every job.
- You want the longest possible work cycle without manual refilling, because the tank is fed from the mains.
Choose the mobile machine when
- Vehicles are parked across a yard, a street or several locations, and bringing them all to one bay would take more time than the cleaning itself.
- There is no practical way to run a dedicated circuit, water line and drain to a single wash position.
- The same team cleans several different areas, and the machine has to travel between them.
- Narrow garages and parking spaces are the main working environment, where the slim body is the deciding feature.
Some sites need both
A common arrangement is a fixed unit at the main bay for volume work, plus a mobile unit for overflow and for areas outside the fixed machine's hose reach. If you plan this, check two things before ordering: that one charging place and one water point can serve the combined routine without queues, and that the same operators can run both machines after a single training session.
Run one day of real work before ordering
The comparison above narrows the field; a trial decides it. Pick two representative vehicles with your typical soiling, write down what counts as clean and what drying time you can accept before the trial starts, then run each form factor on an equivalent job. Record the time from start to hand-back, the number of vehicles completed per hour, how many refills and battery swaps were needed, and the drying time. Compare the two records against your written standard, not against impressions. A machine that looks capable on a specification sheet can still lose a day like this on your own site conditions.
Questions to send the supplier before you order
- The steam temperature and pressure of the mobile model in writing, since these are not published on its page.
- Battery capacity, run time per charge, charger output, and exactly what ships with the including-battery and without-battery versions.
- For the fixed machine, the hose and cable reach from the installed position, and the water inlet and drainage requirements at that point.
- How waste water is expected to be handled, and which drainage requirements you need to confirm with your local authority.
- Spare parts availability, warranty terms and operator training for whichever form factor you choose.
The two specification tables answer different questions, and that is exactly what makes the decision: compare them against what your site can support at one fixed point, and against what your team can keep running on a battery and a tank. If you want a second opinion on your layout before choosing, send your site notes and vehicle types to the PowerDe team through the contact page and ask for a recommendation between the two form factors.
