SharkBU3521UK

How we test carpet cleaning

This score shows how well the vacuum cleaner sucks up fine Arizona desert sand from deep within the pile of Wilton carpets. The best models will suck up as much as eight times more than the worst.

How we test allergen retention

This test is particularly important for serious allergy sufferers who want to remove all of the fine dust and allergens they can from their home. A five-star score here means that nearly all of the fine dust and allergens that the vacuum cleaner picks up are locked tightly within the container and are not released back into the home.

How we test cleaning with a full dust container

How well the vacuum sucks up dust from crevices when the dust container is full. If you want to compare how well this vacuum cleans when the vacuum is full, and empty, then compare the floorboard star rating, with this one.

How we test noise

The more stars the quieter this model is compared to others we have tested.

How we test battery life and recharging

The best batteries last for up to an hour and don't take long to recharge. The worst will give you less than twenty minutes of power and take more than half a day to fully recharge.

How we test energy consumption

How much energy the cordless vacuum cleaner uses, both while in use and also in standby mode.

How we test ease of use

How easy it is to regularly clean and maintain the vacuum cleaner including changing and replacing filters and emptying and cleaning the dust canister.

How we test floorboard cleaning

This score shows how well each cordless vacuum cleaner picks up dust from in between the crevices that you find between traditional floorboards. While some cordless vacuums will comfortably suck up dust from a flat hard surface, floorboards with deep crevices often prove a lot more challenging.

How we test laminate floor cleaning

This score shows how well each cordless vacuum cleaner sucks up fine dust from hard flat floors such as laminate. A five-star score here means that your hard flat floors will be left spotless.

How we test large debris

This score shows how well each cordless vacuum cleaner sucks up large debris, like rice and lentils, from flat hard surfaces. A five-star score here means that your hard flat floors will be left spotless of any large debris, one-star means much will be left behind or scattered around the floor.

How we test pet hair removal

Pet owners will want to play close attention to the results of this test. First we comb real cat and dog hair into a section of carpet to simulate how trodden in and engrained it can get in a real home. We then time how long it takes each cordless vacuum cleaner to suck it all up. A great cordless vacuum cleaner can suck it all up in less than 20 seconds, the worst leave hair behind even after two minutes of continuous cleaning.

How we test fibre removal

How quickly the cordless vacuum cleaner can suck up lint and fibres from upholstery.

How we test cleaning on minimum power

How well the vacuum cleaner cleans on flat hard floors on its minimum power setting. 1 star means that the cordless vacuum is almost ineffective on its minimum setting, whereas 5 star means you will get excellent results even when maximising your cordless vacuums battery life.

How we test floor coverage

This score shows you how close to walls and corners the floorhead cleans. Some cordless vacuum cleaners have suction channels that do not extend right to the edges of the floorhead and so can leave large uncleaned margins around the edge of rooms. The more stars, the closer the floorhead gets to the edges.