A steam cleaner works rather like a pressure cooker: water is heated in a sealed boiler until it boils, and the steam is then released in measured amounts through the steam gun. The higher the pressure, the faster the steam leaves and the more dirt it shifts. Depending on the machine, boiler pressure rises to as much as 4 bar, and heating takes roughly one to six minutes per litre of water.
Steam is a remarkably economical way to clean: one litre of ordinary tap water becomes 1,700 litres of steam, which is enough for about 20 minutes of steam cleaning. Electricity is needed only for the heating time, and no chemicals are involved — the combination of steam force and temperature does the work on its own.
The short version
Boiler or vaporiser? The decision underneath everything
Two systems compete, and the difference governs how a machine behaves.
Vaporisers evaporate water slowly over a heating element. They are ready to use faster and can be topped up at any time.
Boilers heat the entire water supply and release the resulting overpressure as steam. They reach a markedly higher pressure and sustain it far longer.
Kärcher in particular builds larger pressure boilers in which the whole water supply is heated and vaporised, which costs preparation time and buys steam force.
The winner: Kärcher SC 2 Deluxe EasyFix
The SC 2 Deluxe offers the largest water supply of the machines here and works at 3.2 bar. Its accessory set is extensive, the steam pressure is high and — importantly — steam output is even rather than surging.
It doubles as a steam mop: two extension tubes, each 50 cm long, turn the hand unit into a broom, and their oval section and deeply interlocking joints keep the assembly rigid. Two stops on the trigger limit its travel, giving continuous, regulated steam output rather than an all-or-nothing blast.
Build quality is high. The drawback is that the water tank is not removable, so refilling means taking the machine to the tap rather than the other way round.
It takes first place ahead of larger, more expensive machines largely because it costs less to buy while doing the essential job just as well.
The most versatile: Hoover Steam Capsule 2in1
The Steam Capsule ought really to be called a 10-in-1. No other steam cleaner here offers such a range of functions at good quality and a sensible price, and the reason is one design decision: a detachable hand unit that lifts out of the body in a single movement and works independently.
For accessories and sheer usefulness it is hard to beat — flexible hose, large and small mop heads, even brass brushes. The floor nozzle's steam distribution impressed particularly: the cloth is flooded and dampened evenly across its whole area in very little time. The two-part foot shrinks quickly so corners are easy to reach.
It gives way on small details rather than large ones: lower steam output than the Kärcher, round brushes that need an adapter and emit an unpleasant whistle in use, and a small water tank that is awkward to fill. Accept those compromises and it is the most flexible machine here.
The premium choice: Polti Vaporetto Smart 110 Eco
The Polti's argument is that it refuses the boiler-versus-vaporiser trade-off. It combines a pressure boiler for higher steam pressure with the ability to refill while it is running — something very few machines manage — and pairs that with a large water supply and stepless steam regulation.
Because the whole supply is heated once, it produces steam without interruption and the longer warm-up happens only once. For mopping, the base unit stays on the floor and rolls along behind you, and a 1.6 m hose combined with a 4 m cable gives a working radius of nearly six metres.
That combination is what displaced the previous luxury recommendation. It is expensive, which is the honest catch.
The budget pick: Vileda Steam Plus
No technical highlight, and beyond stepless steam regulation it offers no settings at all — a pure steam mop with no accessories. But it works, produces enough steam, and is above all extremely manoeuvrable, which matters more in practice than a specification sheet suggests.
It switches on at a rotary control that also sets the steam volume. The first puffs arrive after about 30 seconds, and it takes roughly another 30 seconds before the microfibre cloth is dampened across its full area — so despite drawing 1,550 W it is not especially quick off the mark, though there is never a shortage of steam. Hook the wound cable onto the base and it stands about 70 cm high for storage.
Also tested
The Kärcher SC 5 EasyFix was previously the luxury recommendation and now sits among the also-tested machines, displaced by the Polti. It remains a strong device on paper — 2,200 W and 4.2 bar — and the Kärcher SC 3 Deluxe EasyFix manages 3.5 bar with a 1-litre capacity. Steam mops as a category are clearly dominated by Kärcher; only the Hoover matches them, and it does so through innovation rather than raw pressure.
How to choose
Decide boiler or vaporiser first. If you want maximum dirt-shifting force and will tolerate a wait, choose a pressure boiler. If you want to start quickly and top up mid-job, choose a vaporiser — or the Polti, which does both.
Check whether the tank comes off. The winner's does not, which is its single real inconvenience.
Count the accessories you will genuinely use. The Hoover's detachable hand unit and brush set make it the most adaptable; the Vileda has essentially none, and is cheaper for it.
Watch the pressure figure, but not only that. Between 3.2 bar on the winner and 4 bar at the top of the range, the practical differences are steam speed and how long the pressure holds.
Consider fill and heat time. Heating takes roughly one to six minutes per litre depending on the machine, which is the difference between grabbing it for a spill and planning to use it.
Frequently asked questions
Which steam cleaner should I buy? The Kärcher SC 2 Deluxe EasyFix — the largest water supply here, 3.2 bar, even steam output, high build quality and extensive accessories, at a lower purchase price than the machines above it.
How does a steam cleaner actually work? Like a pressure cooker. Water is heated in a sealed boiler until it boils, then released in measured amounts through the steam gun. Pressure reaches up to 4 bar, and higher pressure means faster steam and more cleaning force.
How long does it take to heat up? Roughly one to six minutes per litre of water, depending on the machine.
What is the most versatile model? The Hoover Steam Capsule 2in1, whose detachable hand unit works independently and comes with a flexible hose, two mop sizes and brass brushes — at the cost of lower steam output and a small, awkward tank.
Can I refill one while it is running? Only some. Vaporisers can be topped up at any time; pressure boilers generally cannot. The Polti Vaporetto Smart 110 Eco is the unusual machine that offers boiler pressure and mid-use refilling together.
Is the cheapest option any good? The Vileda Steam Plus has no accessories and only stepless steam regulation, but it produces enough steam and is extremely manoeuvrable.
