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30 June 2021

Cordless vacuum cleaners glossary

Below we explain the features, terms and accessories you'll encounter as you shop for a cordless vacuum.
Matthew Knight

Once you've decided on the features that would suit you, take a look at our Best Buy cordless vacuum cleaners

We've tested some of the latest and most popular cordless vacuum cleaners from brands such as Dyson, G-Tech and Bosch, and found big differences between them – our top-scoring model gets 80%, while the lowest ones scored only 42%.

Accessories for cordless vacuum cleaners

Some cordless vacuum cleaners come with additional tools to help with specific tasks, such as stiff brushes for cleaning stubborn dirt, soft brushes for upholstery, or smaller nozzles for tight spaces. These accessories can sometimes be stored on the machine itself so they're conveniently stowed while you move around the house, while others need to be stored separately.

Allergen retention

This refers to how well a vacuum cleaner is able to trap and lock away the fine particles or dust or pollen it sucks up. Some models leak out a significant portion of fine particles, which is why we give each vacuum cleaner we test a rating for allergen retention out of fine. You can look up allergen retention scores on the 'Test results' page of each review. Also see 'dust retention' and 'filters' below.


All cordless vacuum cleaners are bagless, meaning that dirt is trapped inside a canister that you then empty into a bin. This does save you the hassle and cost of replacing bags, but emptying a bagless vacuum cleaner can be a messy job, potentially making them a bad choice for those with allergies.

Battery life

As cordless vacuum cleaners can't be plugged in to the mains, you’ll be relying on battery power. This means a cordless vacuum cleaner can't clean for as long as conventional ones – they can run for anything between 15 and 60 minutes.

If you choose to use the maximum power setting (often called 'boost' or 'turbo' mode), which is suppose to increase the amount of dirt it can pick up, this is also likely to reduce the amount of battery life it has.

It’s also worth keeping in mind that in our tests we’ve found that actual running times are often different to the claimed ones. Our reviews show how long each vacuum cleaner lasts for on its most powerful setting.


The capacity or size of a vacuum cleaner’s canister determines how much dust it can hold, which is measured in litres. The capacity is usually smaller than you'll find on a conventional corded vacuum cleaner, which hold 2 to 3 litres. Cordless vacuum cleaners typically have capacities between 0.3 to just over 1 litre.

Charge time

This is the amount of time the manufacturer states that it will take to recharge the battery to 100% on the cordless vacuum cleaner. This can range from anything between two hours and more than 16 hours.

Detachable handheld

Some cordless vacuum cleaners have a detachable handheld unit than can be used for reaching into small or difficult-to-reach places. The cordless vacuums that come with this extra are usually called '2-in-1' cordless vacuums.

Docking station

Also called a charging station, this is a dock that the vacuum cleaner sits in to charge. These stations are often wall-mountable, which can make them easier to store.

Dust retention

As well as having a cordless vacuum cleaner that can pick up dust, it’s also important that it keeps the dust inside – we’ve found ones that let almost 20% of the dust back out. We use specialist machinery to test how much dust and fine particles the cordless vacuum cleaners can retain instead of sending it back into your home. Each model tested in our cordless vacuum cleaner reviews are given a star rating for this, under 'allergen retention'.

Electrostatic shocks

You can get these from a vacuum cleaner if earthed surfaces are touched. Various factors determine the likelihood and severity of shocks, but the main factors that affect this are humidity, the kind of dust that's sucked in the material of the floor and the material of the shoes you're wearing. One way to reduce the likelihood of getting shocks is to lie the handle of the vacuum down on the floor at regular intervals to discharge any build up of static.

Extendable hose

Also sometimes called a flexi hose, this attachment allows you to reach awkward places. Keep in mind that not all cordless vacuum cleaners have this as an accessory.


Cordless vacuum cleaner filters can clog up and need cleaning or changing at least once a year. How easy it is to clean or change the filter is something we test for in our test lab, and one cordless vac only gained two stars for this.

Handheld vacuum cleaner

Unlike cordless vacuum cleaners, which tend to look and work more like upright vacuum cleaners, handheld vacs are small and are useful for quickly cleaning small areas, such as in your car, and small amounts of dirt, such as crumbs. Some cordless vacuum cleaners can be converted into a handheld – see our section below on two-in-one cordless vacuums.

Hepa filter

Hepa filters are designed to keep particles trapped inside the vacuum and only emit air that is safe for allergy sufferers. Some machines with this feature are given approval by the British Allergy Foundation. We test the reliability of this, and have found cordless vacuum cleaners scoring just two stars for allergen retention.

Low battery indicator

Many cordless vacuum cleaners have a light to show you when the battery is getting low, and when it’s fully charged.


As with tests of conventional vacuum cleaners, we measure the noise of cordless vacuum cleaners – and some are really loud and annoying. We've found models that registered decibel readings of 88, which is equivalent to loud traffic on a busy road. But many only get up to 75 decibels, which means they earn four or five stars for noise.

Pet hair pick-up

In our tests we see just how easily and well cordless vacuum cleaners pick up pet hair. Many of the cordless vacuum cleaners we have tested achieve four or five stars for this test, while some get less than three – not ideal if you have pets and have bought a cordless vac to blitz the worst of the hairs day to day.

Running time

This is linked to the battery life and how long the manufacturer says the vacuum cleaner can run for on a full battery. The claimed running time can vary from what we’ve measured in our test lab.

S class filter

Another name for Hepa filters.


Cordless vacuum cleaners tend to be easier to store than normal upright vacuum cleaners as they are smaller and lighter. Some cordless vacuum cleaners can be stored in their docking station, which can often be wall-mounted.

Turbo boost

Some cordless vacuum cleaners come with a turbo-boost option, so that you can clean with increased power. This does tend to decrease the amount of time you can vacuum on a fully charged battery though.

Turbo tool / Turbo brush

An additional attachment for your cordless vacuum cleaner which has motorised brushes inside to help loosen hair, fur and ground-in dirt. A turbo brush may improve dust and pet hair pick-up but in some cases our testing has found that standard nozzles can be just as effective.

Two-in-one / 2-in-1 cordless vacuum cleaners

Some cordless vacuum cleaners are two-in-one models, which means they can be used like an upright vacuum cleaner, or the body can be removed to be used as an ultra-portable handheld vacuum cleaner. This type of vacuum is often called a 'cordless handheld'.


The wattage of cordless vacuum cleaners tends to be lower than that of normal vacuum cleaners – between 140 and 500 watts, as opposed to 2,200 watts for some of our Best Buys corded vacuum cleaners. A high wattage is often used as a selling point for vacs by manufacturers, but good cleaning comes from design and suction, not how high the wattage is. High wattage doesn’t necessarily mean you’ll get a better vacuum cleaner, but it does mean you’ll use more energy.