As both a vacuum cleaner and a carpet cleaner, I put the Karcher SE 4001 through both sets of tests. First, I measured raw performance in AirWatts (AW), which combines airflow with suction power. The higher the number, the better. The SE 4001 returned a result of 281AW, which is one more than the Dyson V15 Detect on Boost mode. That’s a lot of power. There’s a fair amount of assembly required before you can get going with this vacuum, particularly if you want to use it as a carpet cleaner. To test stain removal, I ran my usual carpet tests. First, I spread a tablespoon of ketchup onto test carpet, and allowed it to dry. Using a combination of spray and suction, I managed to get most of the stain out –although you can still see traces remaining. Rather than sporting a more modern carpet cleaner design, of an upright vacuum cleaner with a motorised brush, the Karcher SE 4001 looks more like a regular wet and dry vacuum cleaner, such as the Karcher WD4.

I found the carpet cleaner less successful on dirty carpet tiles, however. Without a brush bar to agitate the dirt, the Karcher really struggled to lift out the dirt. First, you have to attach the hose and extension tubes, after which there’s a selection of accessories. For wet and dry use, there’s a floor head with a clip-in carpet brush, plus a crevice tool. Next, I ground in a tablespoon of mud onto the carpet, again leaving it to dry. This time, the SE 4001 managed to remove everything with ease.Since this is a wet and dry vacuum cleaner, I then ran my normal test. Crushing up a wet Weetabix, I spread the mess onto the hard floor. A single pass left a clean strip through the middle. A large cylinder cleaner, the Karcher SE 4001 is a bit of a beast at 441 x 386 x 537mm and weighing 7.9kg. Fortunately, you can attach the set of wheels to the bottom of it, so you’ll mostly be wheeling this unit around. Once attached, there’s a spray handle that puts cleaning solution onto the carpet, provided you’ve turned on the water pump, which is separate from the main power button.

For carpet cleaning, there’s a single nozzle in the box, which has a slide-in rubber attachment so that you can use it for hard floors. One of the problems faced by many is ending up with too many appliances that rarely get used. The Karcher SE 4001 could be good for the majority, then: it’s a carpet cleaner and a wet and dry vacuum cleaner, so you can use it for pretty much all types of floor surface.