The Duplex 280 is for small, cramped areas such as bathrooms and kitchens. The 340 suits small to medium floors, and the 420 is the one to buy for medium areas or anywhere you clean every day. All three are corded cylindrical-brush scrubbers that wash, scrub and dry in one pass, right to the skirting. They differ mainly in width, tank size and how many square metres an hour they cover.
They also share the floors they’re best on: textured non-slip tiles, grout and short-pile carpet, where a flat-pad scrubber struggles.
How do the Duplex 280, 340 and 420 compare?
The model number is the cleaning width in millimetres. Here are the manufacturer’s figures side by side.
| Duplex 280 | Duplex 340 | Duplex 420 | |
|---|---|---|---|
| Cleaning width | 280 mm | 340 mm | 420 mm |
| Coverage | 100 to 250 m²/h | 200 to 300 m²/h | 300 to 500 m²/h |
| Solution tank | 1.5 L | 4.2 L | 5.4 L |
| Recovery tank | 0.8 L | 1.9 L | 2.3 L |
| Weight | 13 kg | 27.5 kg | 27.5 kg |
| Power | Corded | Corded | Corded |
| Steam version | No | Yes, 340 Steam | Yes, 420 Steam |
Specifications: Duplex Cleaning Machines Australia product pages, October 2026.
The 340 and 420 weigh the same and share a body length. The 420 gets you a wider path, a bigger tank and up to 500 square metres an hour for no extra weight. That’s why it’s the most popular machine in the Duplex range.
Which floors are Duplex machines best on?
Duplex machines do their best work on textured and non-slip floors, carpet tiles and short-pile carpet. Two contra-rotating cylindrical brushes reach down into grooves and grout lines that a flat disc rides over.
That matters more than people think. Shaun Herman, who runs CC Machines, checks the floor surface on every site walk: “if it’s non slip we run a different unit to if it’s flat and smooth.” In aged care bathrooms and commercial kitchens, the non-slip floor is usually what decides it for a Duplex.
The 420 comes with four brush choices. Black is for heavy-duty scrubbing, grey for hard floors and short carpet, yellow for short to medium pile carpet, and brown, a horsehair brush, for gentle brushing. With a brush change, the same machine can do a vinyl corridor in the morning and carpet tiles in the afternoon.
On a large, smooth, sealed warehouse slab, a Duplex is the wrong tool. A disc or ride-on scrubber covers that floor faster. Our guide to choosing a commercial floor scrubber covers the other machine types.
When is the Duplex 280 the right choice?
Choose the 280 when the space is tight and the area is small. At 13 kilograms with a 280 mm path, it gets under tables, around toilet pans and into the corners of a commercial kitchen. A shower room is the kind of space it suits.
The trade-off is its tanks. The 1.5 litre solution tank and 0.8 litre recovery tank mean frequent emptying on anything bigger than a few rooms. At up to 250 square metres an hour, a 400 square metre floor takes the 280 at least an hour and a half, plus refills. The 420 can do that floor in under an hour and a half even at its slowest.
340 or 420: which should you buy?
For most buyers it comes down to these two, and the 420 usually wins. It covers more floor, holds more water and weighs the same. Pick the 340 when the narrower body genuinely matters: tight doorways, cluttered rooms, or operators who find the wider machine harder to steer.
| Your site | Usually suits |
|---|---|
| Bathrooms, ensuites, a small commercial kitchen | 280 |
| Classrooms, consulting rooms, small retail | 340 |
| Aged care wings, hotel corridors, mixed tile and carpet | 420 |
| Kitchens or wet areas that need sanitising without chemicals | 340 Steam or 420 Steam |
| Larger open areas still on textured floors | Ask about the 620 |
The steam versions add a boiler that puts 130°C steam onto the floor as it scrubs. They’re worth it in kitchens, bathrooms and healthcare areas where you want to sanitise as you go.
What about the power cord?
All three run off mains power, which keeps them light and means no battery to replace. The catch is the lead. On a big floor someone has to manage it, and you need a power point nearby.
If the cord is a real problem on your site, Duplex also makes battery machines. We sell the Duplex Lithium, Lithium Evolve and Lithium Hybrid. Ask us to bring one along to a demonstration so you can compare.
How long do Duplex machines last?
With correct maintenance, a long time. Duplex machines have few moving parts. We service 340s and 420s across Queensland every six or twelve months for compliance, and some are still running well after more than 25 years.
The habits that bring any scrubber into our workshop early apply here too, and recovery tanks left full is the big one. Our floor scrubber maintenance tips apply to Duplex as much as anything else.
Buying a Duplex in Brisbane
We’re an authorised Duplex dealer and do Duplex warranty repairs, with genuine parts held at our Brendale workshop. Duplex machines are quoted, not listed, so call for the price on the model and brushes you need. Scheduled servicing starts from $220 ex GST a visit.
Our largest customers include aged care and hospital groups, the kind of sites where Duplex machines earn their keep. A demonstration on your own floor is the quickest way to settle 340 versus 420.
Common questions
What is the difference between the Duplex 340 and 420?
The 420 cleans a 420 mm path against the 340’s 340 mm, holds 5.4 litres of solution against 4.2, and covers up to 500 square metres an hour against 300. Both weigh 27.5 kilograms.
Can a Duplex clean carpet?
Yes, short and medium pile carpet and carpet tiles, with the right brush fitted. The 420 has a dedicated carpet brush.
Is the Duplex 420 battery powered?
No, the standard 420 is corded. Duplex makes separate lithium battery machines if you need to work away from power points.
How much does a Duplex 420 cost?
We quote Duplex machines once we know the model, brushes and whether you want the steam version. Call 1300 343 246 with the model and brushes you have in mind.
Book a Duplex demonstration
See the full Duplex range, or call 1300 343 246 to book a demonstration of the 340 and 420 side by side on your floor.
