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Shark BU3521EU Review | 52 Data compared

Avg. price:~£150Suction power (AW):65 AWBattery runtime:40 minutesCapacity:0.42 LWeight:2.7 kg

Shark BU3521EU Review: Compare 52 technical specifications and user reviews to see how this product ranks in the Vacuum Cleaners category and whether it is worth buying.

6.6

Overall score

Score
6.6/ 10
✕
What it is
An overall evaluation of the vacuum cleaner's quality, based on technical analysis and user reviews.
When it matters
When you need a quick reference for identifying the best vacuum cleaners on the market.
Score distribution
â–¼
<55-66-77-88-99-10
â–¼ Worse than 67% of models
Score components

80%

6.6

Technical Score

20%

?

User score

â–¼Worse than 67% of vacuum-cleaners
6.6

Technical Score

Technical score
6.6/ 10
✕
What it is
An assessment of the vacuum cleaner's technical performance across six key areas: performance, battery and power supply, filtration, attachments, design, and smart features.
When it matters
When you want to compare vacuum cleaners by cleaning performance, specifications, and available features.
Score distribution
â–¼
<55-66-77-88-99-10
â–¼ Worse than 52% of models
Score components

28%

4.9

Performance

22%

6.4

Battery

18%

8.5

Filtration

14%

7.0

Attachments

10%

7.0

Design

8%

7.0

Smart features

â–¼Worse than 52% of vacuum-cleaners
?

User score

User score
8.0/ 10
✕
What it is
A rating that combines user reviews with the total number of reviews received by the vacuum cleaner.
When it matters
When you want to know how a vacuum cleaner performs in everyday use and how reliable owners find it over time.
Score distribution
â–¼
<55-66-77-88-99-10
â–¼ Worse than 73% of models
Score components

70%

?

User ratings

30%

?

Number of reviews

  • No image
No image

Best prices

    N/A~ £150
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Best rankings

Available: ranking among products currently available (including other versions of this product).All: ranking among all products in the database.
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Verdict

The Shark BU3521EU Clean & Empty is a 2-in-1 cordless stick and handheld vacuum cleaner weighing 2.7 kg, designed for carpets and hard floors with an auto-adjusting FloorDetect multi-surface brushroll. Key features include up to 40 minutes of runtime in ECO mode, a 0.42L integrated dustbin, and an innovative, bagless 1.3L auto-empty charging dock that seals away 99.9% of dust and allergens via a HEPA filter for up to 30 days. Main pros include its lightweight maneuverability, the self-cleaning Anti Hair Wrap brushroll, automated hands-free maintenance, and integrated LED headlights that reveal hidden debris. On the downside, the suction power reduces battery runtime significantly when operating in Boost mode, the dock requires a larger physical storage footprint compared to traditional wall mounts, and it may struggle to pick up larger debris chunks.

Technical Specifications of vacuum cleaner Shark BU3521EU

Technical Score
Technical score
6.6/ 10
✕
What it is
An assessment of the vacuum cleaner's technical performance across six key areas: performance, battery and power supply, filtration, attachments, design, and smart features.
When it matters
When you want to compare vacuum cleaners by cleaning performance, specifications, and available features.
Score distribution
â–¼
<55-66-77-88-99-10
â–¼ Worse than 52% of models
Score components:

28%

4.9

Performance

22%

6.4

Battery

18%

8.5

Filtration

14%

7.0

Attachments

10%

7.0

Design

8%

7.0

Smart features

6.6
Shark BU3521EU has a technical score of 6.6 points, which is lower than 51.7% of vacuum cleaners.
User score
User score
8.0/ 10
✕
What it is
A rating that combines user reviews with the total number of reviews received by the vacuum cleaner.
When it matters
When you want to know how a vacuum cleaner performs in everyday use and how reliable owners find it over time.
Score distribution
â–¼
<55-66-77-88-99-10
â–¼ Worse than 73% of models
Score components

70%

?

User ratings

30%

?

Number of reviews

?
Popularity
Popularity
1.0/ 10
✕
What it is
An indicator based on the number of reviews received by the vacuum cleaner.
When it matters
When you prefer a vacuum cleaner that has been chosen and reviewed by many other buyers.
Score distribution
â–¼
<55-66-77-88-99-10
â–¼ Worse than 99% of models
Popularity:
Shark BU3521EU has a popularity score of 1 point, which is lower than 61.7% of vacuum cleaners.
1.0
Shark BU3521EU has a popularity score of 1 point, which is lower than 61.7% of vacuum cleaners.
Ratio quality/price
Value for money
7.5/ 10
✕
What it is
An indicator that combines the vacuum cleaner's overall score with its price.
When it matters
When you are looking for a vacuum cleaner with a good balance between quality and price.
Score distribution
â–¼
<55-66-77-88-99-10
â–¼ Worse than 70% of models
Score components:

60%

6.6

Overall score

40%

9.7

Price

7.5
Shark BU3521EU has a value-for-money score of 7.5 points, which is lower than 60.9% of vacuum cleaners.
Suction power (AW)
65 AW
Suction power (AW)
65 AW
â–¼ Worse than 86% of models
Market range: <40 AW – >280 AW
This vacuum cleaner has a suction power of 65 AW, which is lower than that of 85.7% of vacuum cleaners and equal to that of 0.9% of vacuum cleaners.
Suction power (kPa)
10 kPa
Suction power (kPa)
10 kPa
â–¼ Worse than 92% of models
Market range: <11 kPa – >30 kPa
This vacuum cleaner has a suction pressure of 10 kPa, which is lower than that of 92% of vacuum cleaners and equal to that of 1.6% of vacuum cleaners.
Airflow
?
Motor type
brushless
Power consumption
240 W
Power consumption
240 W
â–² Better than 81% of models
Market range: <165 W – >899 W
This vacuum cleaner draws 240 W, which is lower than the power consumption of 81.4% of vacuum cleaners and equal to that of 1.5% of vacuum cleaners.
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Cordless
yes
Cordless
yes
â–² Better than 51% of models
This vacuum cleaner works cordlessly. 49.5% of vacuum cleaners offer cordless operation.
Battery runtime
40 minutes
Battery runtime
40 minutes
â–¼ Worse than 64% of models
Market range: <30 minutes – >70 minutes
This vacuum cleaner offers a battery runtime of 40 minutes, which is shorter than that of 64.1% of vacuum cleaners and equal to that of 18.6% of vacuum cleaners.
Charging time
5 hours
Charging time
5 hours
â–¼ Worse than 74% of models
Market range: <3 hours – >5 hours
This vacuum cleaner charges in 5 hours, which is slower than 73.8% of vacuum cleaners and equal to 20.4% of vacuum cleaners.
Battery capacity
2,500 mAh
Battery capacity
2,500 mAh
â–² Better than 48% of models
Market range: <2k mAh – >3.6k mAh
This vacuum cleaner has a battery capacity of 2,500 mAh, which is larger than that of 48.1% of vacuum cleaners and equal to that of 24.7% of vacuum cleaners.
Battery voltage
21.6 V
Battery voltage
21.6 V
â–¼ Worse than 60% of models
Market range: <18 V – >28.8 V
This vacuum cleaner uses a battery voltage of 21.6 V, which is lower than that of 59.8% of vacuum cleaners and equal to that of 16.5% of vacuum cleaners.
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Filter class
hepa 12
Filter class
hepa 12
â–² Better than 74% of models
This vacuum cleaner uses filter class hepa 12, which is more advanced than the class used by 74.4% of vacuum cleaners and the same as the class used by 5% of vacuum cleaners.
Minimum overall efficiency
99.97%
Minimum overall efficiency
99.97%
â–² Better than 59% of models
Market range: <95 % – >99.99 %
This vacuum cleaner reaches 99.97% minimum overall efficiency, which is higher than that of 59.1% of vacuum cleaners and equal to that of 19.4% of vacuum cleaners.
Suitable for allergy sufferers
yes
Suitable for allergy sufferers
yes
â–² Better than 18% of models
This vacuum cleaner is suitable for allergy sufferers. 82.4% of vacuum cleaners are allergy-friendly.
Capacity
0.42 L
Capacity
0.42 L
â–¼ Worse than 90% of models
Market range: <0.44 L – >4 L
This vacuum cleaner has a dust capacity of 0.42 L, which is smaller than that of 90.2% of vacuum cleaners and equal to that of 0.3% of vacuum cleaners.
Bagless
yes
Bagless
yes
â–² Better than 21% of models
This vacuum cleaner uses a bagless design. 78.6% of vacuum cleaners use this setup.
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Main brush type
roll brush
Roller type
bristled
Anti-tangle brush
yes
Anti-tangle brush
yes
â–² Better than 74% of models
This vacuum cleaner includes an anti-tangle brush. 25.7% of vacuum cleaners include this feature.
Mini motorized brush
no
Mini motorized brush
no
â–¼ Worse than 27% of models
This vacuum cleaner does not include a mini motorized brush. 26.9% of vacuum cleaners include this attachment.
Suitable for pet owners
yes
Suitable for pet owners
yes
â–² Better than 28% of models
This vacuum cleaner is suitable for pet owners. 72% of vacuum cleaners handle pet hair well.
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Vacuum type
stick
Weight
2.7 kg
Weight
2.7 kg
â–² Better than 70% of models
Market range: <2.15 kg – >7.1 kg
This vacuum cleaner weighs 2.7 kg, which is lower than the weight of 70.1% of vacuum cleaners and equal to that of 2.4% of vacuum cleaners.
2-in-1 design
yes
2-in-1 design
yes
â–² Better than 47% of models
This vacuum cleaner offers a 2-in-1 design. 53% of vacuum cleaners offer this flexible format.
Self-standing
no
Self-standing
no
â–¼ Worse than 19% of models
This vacuum cleaner does not stand on its own. 18.9% of vacuum cleaners offer this convenience.
Adjustable tube height
no
Adjustable tube height
no
â–¼ Worse than 47% of models
This vacuum cleaner does not include adjustable tube height. 47.4% of vacuum cleaners offer this ergonomic feature.
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Auto suction adjustment
yes
Auto suction adjustment
yes
â–² Better than 80% of models
This vacuum cleaner supports automatic suction adjustment. 19.9% of vacuum cleaners support this feature.
Dust particle sensor
no
Dust particle sensor
no
â–¼ Worse than 8% of models
This vacuum cleaner does not include a dust particle sensor. 8% of vacuum cleaners include this feature.
LED display
no
LED display
no
â–¼ Worse than 26% of models
This vacuum cleaner does not include an LED display. 25.9% of vacuum cleaners include this interface feature.
Nozzle light
yes
Nozzle light
yes
â–² Better than 57% of models
This vacuum cleaner includes a nozzle light. 43.4% of vacuum cleaners include this visibility feature.
Mopping support
no
Mopping support
no
â–¼ Worse than 4% of models
This vacuum cleaner does not support mopping. 3.7% of vacuum cleaners support this multi-function feature.

Shark BU3521EU vs the average vacuum cleaner

246810TotalPerformanceBatteryFiltrationAttachmentsDesignSmart features
  • Cordless operation
    Cordless
    yes
    â–² Better than 51% of models
    This vacuum cleaner works cordlessly, the average vacuum cleaner does not.
  • Includes anti-tangle brush
    Anti-tangle brush
    yes
    â–² Better than 74% of models
    This vacuum cleaner includes an anti-tangle brush, the average vacuum cleaner does not.
  • Higher filter class
    Filter class
    hepa 12
    â–² Better than 74% of models
    This vacuum cleaner uses a better filter class than the average vacuum cleaner (hepa 12 vs hepa).
    hepa 12 vs hepa
  • Automatic suction adjustment
    Auto suction adjustment
    yes
    â–² Better than 80% of models
    This vacuum cleaner supports automatic suction adjustment, the average vacuum cleaner does not.
  • Includes removable battery
    Removable battery
    yes
    â–² Better than 61% of models
    This vacuum cleaner includes a removable battery, the average vacuum cleaner does not.
  • Includes full bin indicator
    Full bin indicator
    yes
    â–² Better than 73% of models
    This vacuum cleaner includes a full bin indicator, the average vacuum cleaner does not.
  • Includes nozzle light
    Nozzle light
    yes
    â–² Better than 57% of models
    This vacuum cleaner includes a nozzle light, the average vacuum cleaner does not.
  • 360 W lower power consumption
    Power consumption
    240 W
    â–² Better than 81% of models
    Market range: <165 W – >899 W
    This vacuum cleaner draws less power than the average vacuum cleaner (240 W vs 600 W).
    240 W vs 600 W
  • 360 W lower power consumption
    Power consumption
    240 W
    â–² Better than 81% of models
    Market range: <165 W – >899 W
    This vacuum cleaner draws less power than the average vacuum cleaner (240 W vs 600 W).
    240 W vs 600 W
  • 1 more power levels
    Number of speeds
    3
    â–² Better than 56% of models
    Market range: <1 – >4
    This vacuum cleaner offers more speed levels than the average vacuum cleaner (3 vs 2).
    3 vs 2
  • Cordless operation
    Cordless
    yes
    â–² Better than 51% of models
    This vacuum cleaner works cordlessly, the average vacuum cleaner does not.
  • Includes removable battery
    Removable battery
    yes
    â–² Better than 61% of models
    This vacuum cleaner includes a removable battery, the average vacuum cleaner does not.
  • Includes battery indicator
    Battery level indicator
    yes
    â–² Better than 53% of models
    This vacuum cleaner includes a battery level indicator, the average vacuum cleaner does not.
  • Higher filter class
    Filter class
    hepa 12
    â–² Better than 74% of models
    This vacuum cleaner uses a better filter class than the average vacuum cleaner (hepa 12 vs hepa).
    hepa 12 vs hepa
  • Includes full bin indicator
    Full bin indicator
    yes
    â–² Better than 73% of models
    This vacuum cleaner includes a full bin indicator, the average vacuum cleaner does not.
  • 0.02 % higher filtration efficiency
    Minimum overall efficiency
    99.97 %
    â–² Better than 59% of models
    Market range: <95 % – >99.99 %
    This vacuum cleaner has higher filtration efficiency than the average vacuum cleaner (100 % vs 99.95 %).
    99.97 % vs 99.95 %
  • Includes anti-tangle brush
    Anti-tangle brush
    yes
    â–² Better than 74% of models
    This vacuum cleaner includes an anti-tangle brush, the average vacuum cleaner does not.
  • 25.4% lower weight
    Weight
    2.7 kg
    â–² Better than 70% of models
    Market range: <2.15 kg – >7.1 kg
    This vacuum cleaner is lighter than the average vacuum cleaner (2.7 kg vs 3.62 kg).
    2.7 kg vs 3.62 kg
  • Newer release date
    Release date
    2024
    â–² Better than 82% of models
    Market range: <2k – >2k
    This vacuum cleaner has a newer release date than the average vacuum cleaner (2024 vs 2021).
    Released in August 2024.
    2024 vs 2021
  • Automatic suction adjustment
    Auto suction adjustment
    yes
    â–² Better than 80% of models
    This vacuum cleaner supports automatic suction adjustment, the average vacuum cleaner does not.
  • Includes nozzle light
    Nozzle light
    yes
    â–² Better than 57% of models
    This vacuum cleaner includes a nozzle light, the average vacuum cleaner does not.
  • More operating noise
    Noise level (Min-Max)
    80-84 dB
    â–¼ Worse than 86% of models
    Market range: <65 dB – >83 dB
    This vacuum cleaner is noisier than the average vacuum cleaner (80-84 dB vs 77-77 dB).
    80-84 dB vs 77-77 dB
  • 10 kPa lower suction pressure
    Suction power (kPa)
    10.0 kPa
    â–¼ Worse than 92% of models
    Market range: <11 kPa – >30 kPa
    This vacuum cleaner has lower suction pressure than the average vacuum cleaner (10 kPa vs 20 kPa).
    10.0 kPa vs 20 kPa
  • 85 AW lower suction power
    Suction power (AW)
    65 AW
    â–¼ Worse than 86% of models
    Market range: <40 AW – >280 AW
    This vacuum cleaner has lower suction power than the average vacuum cleaner (65 AW vs 150 AW).
    65 AW vs 150 AW
  • 0.58 L smaller dust container
    Capacity
    0.42 L
    â–¼ Worse than 90% of models
    Market range: <0.44 L – >4 L
    This vacuum cleaner has a smaller dust capacity than the average vacuum cleaner (0.4 L vs 1 L).
    0.42 L vs 1 L
  • 1 hours slower charging
    Charging time
    5 hours
    â–¼ Worse than 74% of models
    Market range: <3 hours – >5 hours
    This vacuum cleaner charges slower than the average vacuum cleaner (5 hours vs 4 hours).
    5 hours vs 4 hours
  • 10 minutes shorter runtime
    Battery runtime
    40 minutes
    â–¼ Worse than 64% of models
    Market range: <30 minutes – >70 minutes
    This vacuum cleaner offers shorter battery runtime than the average vacuum cleaner (40 minutes vs 50 minutes).
    40 minutes vs 50 minutes
  • No upholstery nozzle
    Upholstery nozzle
    no
    â–¼ Worse than 68% of models
    This vacuum cleaner does not include an upholstery nozzle, the average vacuum cleaner does.
  • No soft dusting brush
    Soft dusting brush
    no
    â–¼ Worse than 73% of models
    This vacuum cleaner does not include a soft dusting brush, the average vacuum cleaner does.
  • 1.9% worse value for money
    Shark BU3521EU offers worse value for money than the average vacuum cleaner (7.51 vs 7.6).
    7.51 vs 7.65
  • More operating noise
    Noise level (Min-Max)
    80-84 dB
    â–¼ Worse than 86% of models
    Market range: <65 dB – >83 dB
    This vacuum cleaner is noisier than the average vacuum cleaner (80-84 dB vs 77-77 dB).
    80-84 dB vs 77-77 dB
  • 10 kPa lower suction pressure
    Suction power (kPa)
    10.0 kPa
    â–¼ Worse than 92% of models
    Market range: <11 kPa – >30 kPa
    This vacuum cleaner has lower suction pressure than the average vacuum cleaner (10 kPa vs 20 kPa).
    10.0 kPa vs 20 kPa
  • 85 AW lower suction power
    Suction power (AW)
    65 AW
    â–¼ Worse than 86% of models
    Market range: <40 AW – >280 AW
    This vacuum cleaner has lower suction power than the average vacuum cleaner (65 AW vs 150 AW).
    65 AW vs 150 AW
  • 1 hours slower charging
    Charging time
    5 hours
    â–¼ Worse than 74% of models
    Market range: <3 hours – >5 hours
    This vacuum cleaner charges slower than the average vacuum cleaner (5 hours vs 4 hours).
    5 hours vs 4 hours
  • 10 minutes shorter runtime
    Battery runtime
    40 minutes
    â–¼ Worse than 64% of models
    Market range: <30 minutes – >70 minutes
    This vacuum cleaner offers shorter battery runtime than the average vacuum cleaner (40 minutes vs 50 minutes).
    40 minutes vs 50 minutes
  • 0.6 V lower voltage
    Battery voltage
    21.6 V
    â–¼ Worse than 60% of models
    Market range: <18 V – >28.8 V
    This vacuum cleaner has a lower battery voltage than the average vacuum cleaner (21.6 V vs 22.2 V).
    21.6 V vs 22.2 V
  • 0.58 L smaller dust container
    Capacity
    0.42 L
    â–¼ Worse than 90% of models
    Market range: <0.44 L – >4 L
    This vacuum cleaner has a smaller dust capacity than the average vacuum cleaner (0.4 L vs 1 L).
    0.42 L vs 1 L
  • No upholstery nozzle
    Upholstery nozzle
    no
    â–¼ Worse than 68% of models
    This vacuum cleaner does not include an upholstery nozzle, the average vacuum cleaner does.
  • No soft dusting brush
    Soft dusting brush
    no
    â–¼ Worse than 73% of models
    This vacuum cleaner does not include a soft dusting brush, the average vacuum cleaner does.
  • 88 mm deeper body
    Depth
    353 mm
    â–¼ Worse than 72% of models
    Market range: <170 mm – >440 mm
    This vacuum cleaner is deeper than the average vacuum cleaner (353 mm vs 265 mm).
    353 mm vs 265 mm

Graphic comparison of Shark BU3521EU and other vacuum cleaners

No results found

Third-party reviews

What customers like about Shark BU3521EU?

  • Self-draining system: The base station automatically collects dirt and dust and keeps it for up to 30 days, eliminating the hassle of manual emptying.
  • Low weight: The vacuum cleaner is around 30% lighter than comparable models and is therefore very maneuverable and easy to handle.
  • Automatic floor detection (Floor Detect): The brush roll automatically adapts to hard floors and carpets without having to change the brush head.
  • LED lighting: Powerful lighting helps reveal hidden dirt and dust in dark corners.
  • Hair Detangling Technology: The brush roll cleans itself, eliminating the hassle of removing tangled animal or human hair.

What customers dislike about Shark BU3521EU?

  • Filter design in Europe: Compared to the US models of the same series, the European version (EUT) lacks a cyclone and a washable filter, which means the filter can become dirty more quickly.
  • Battery life: With a running time of up to 40 minutes per battery charge, the device may be too limited for very large houses or large-scale operations.
  • Container volume: The actual collecting container on the handheld device is rather small due to its design, as it is designed for automatic emptying at the base.

Expert reviews

In-depth analysis and verdict from leading tech publications

Q
quechoisir.org
27/06/2025
Summary of the review
Shark BU3521EU FloorDetect Cordless Stick Vacuum Review
(Translated)Show original

Video reviews

Hands-on testing, unboxing, and real-world video evaluations

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