Carpet shampooers use a combination of water, concentrated detergent and suction to lift deep-down dirt from your carpet pile when your traditional vacuum or carpet cleaning methods aren't up to the task.
Common cleaning options are to get a professional to do the job for you, or do it yourself with a Britex or Rug Doctor model hired from an outlet like Woolworths, Coles, Mitre 10, IGA or Bunnings.
Hire models typically cost around $40 for 24 hours, or $50 for a weekend, excluding the cost of the cleaning solution and some accessories.
There are also a number of retail models from brands like Bissell, Hoover and Vax which you can buy outright.
The first point to consider is how often will you really be cleaning your carpet?
Carpet shampooers are loud, bulky things that may require frequent water changes depending on the tank capacity and area to be cleaned.
Fortunately, they're not the type of machine you'd use regularly. They tend to be heavy (especially on a full tank) and can be a pain to manoeuvre around. Our carpet shampooer reviews reveal which particular models do the best job and are easy to use.
Carpet shampooers are loud, bulky things that may require frequent water changes
But if you're prepared to put up with the industrial bulk (and don't have to carry it up and down stairs), hiring a model over a weekend is a sensible and cost-effective option, particularly as some of the models in our test cost $900–1600. At that price, you'd have to be using it a lot to get value out of it, unless you're using it across multiple properties or sharing it with someone else.
Also, do check before buying or hiring that the shampooer will fit in your car.
Carpet shampooers bought instore usually come with a small sample of concentrated cleaning solution (detergent) for you to try, but this won't last long, so you'll need to buy extra solution. Check the manufacturer's instructions, as using a detergent that isn't recommended may void the warranty.
Hire machines may require the use of additional defoamer or anti-foamer to reduce excess froth, in addition to the recommended solutions that are on sale at the point of rental.
Major manufacturers sell different types of solutions depending on your needs, such as ones designed to target pet smells or deep-down stains, but using a larger bottle of the solution your shampooer came with is an ideal starting point.
Can you use essential oils in a carpet shampooer?
Always follow the manufacturer's instructions. While essential oils may make your carpet smell nice, if they aren't diluted enough they risk staining your carpet, so it's best to use a cleaning solution designed to work with your machine. The same goes for hydrogen peroxide, a form of bleach which could discolour your carpet.
Large water tanks will make the unit heavier, but may mean less carting of the dirty water to dispose of. A small tank capacity could be lighter to use but may require more refills.
Reach from power point
A long reach saves you from frequently plugging the unit in to different power points around your home. As water is involved, make sure you don't accidentally run over the power cord.
The hire models we tested from Britex and Rug Doctor weigh around 17kg each, and that's without any water in them. The lightest models we've seen are around 5.5kg.
Some models come with this attachment or it's available as an added extra. Check that your furniture is OK to shampoo.
Carpet shampooers can be louder than some lawnmowers we've tested, and the noise can be irritating. Make sure you have protective earmuffs and don't clean with others around, or at odd hours of the day if you have neighbours nearby.
Hard floor tool
Some carpet shampooers allow you to clean hard floors.
Spot treater tools
Although carpet shampooers don't all claim to remove stains, and we test them in their primary configuration as that's their main purpose, you'll find that some come with brush tools to help tackle stubborn spots. Don't expect stains to completely disappear – our test results showed disappointing results, so the most successful treatment for stains is still to soak it up and treat it with a carpet stain remover as soon as it happens.
Manufacturer warranties range from just one year to a more reasonable three years.
Filling and emptying water
Most carpet shampooers come with clean and dirty water tanks – we've seen one model with a 'bladder' situated within one tank that contains clean water, and dirty water gets left outside of this.
Either way, the principle is the same: clean (usually warm tap) water is added, along with solution, and then dirty water must be dispensed with.
Carting the tank to and from the garden or a large sink can be a real chore, especially if the area you're cleaning is very large and the tank itself is quite small, as it'll fill with dirty water really quickly.
If you must pour the dirty water down the drain, make sure you filter the sink to avoid blockages from carpet fluff. Multiple trips with a light tank may still be preferable than emptying a very heavy one.
Moving and using
Carpet shampooers can be tiring to move around, and you should dedicate plenty of time (and patience) to get the job done. In most cases, you'll need to press a trigger or a switch to release the water and cleaning solution, then move the cleaning head slowly back and forth along the carpet while the brushes embed the water into the carpet.
Releasing the trigger or turning the switch off again will then activate suction mode – again you'll need to take it slow and steady, making sure the cleaning head is flush with the carpet to maximise the dirty water being removed.
Some models are trickier to use because they're heavy and cumbersome; some will only suck up water when they're being pulled back, so you'll need to keep moving the unit forward each time.
When we tested carpet shampooers, we were impressed by the lack of residual wetness in general. On a hot day, with the fans on and the windows open, you can expect the carpet to be quite dry within four to six hours. (When we test, we look at how wet the underside of the carpet is as well.)
The more times you go over the carpet in suction mode, the shorter the drying time will be. Take it slowly and follow the manufacturer's instructions. Don't skimp on the suction phase, as leaving too much water in the carpet means it may go mouldy or stale-smelling before it dries.
Models with a clear plastic cleaning head are handy as they allow you to see whether obstructions (such as fluff) are preventing the suction of water. You can also see when the suction has slowed, so you can then move on to cleaning the next section of carpet.
Stock images: Getty, unless otherwise stated.