How to Choose a Bathroom Extractor Fan
Bathroom extractor fans remove moisture, steam, and odors, preventing mold and mildew. This guide explains the key specs to consider so you can pick the right unit for your bathroom size and layout.
Quick answer
For most bathrooms, a 100mm axial fan with a humidity sensor is the best balance of performance and value. The Vent-Axia Lo-Carbon Selwyn is our top pick for its quiet operation, low energy use, and reliable humidistat. For smaller rooms, the Manrose XF100S offers a budget-friendly option.
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Research updated June 2026.
Vent-Axia Lo-Carbon Selwyn 100mm
Quiet, energy-efficient, and with a responsive humidistat.
| Product | Best For | Airflow (L/s) | Noise (dB) | Rating |
|---|---|---|---|---|
| Vent-Axia Lo-Carbon Selwyn | Overall / Quiet | 15 | 24 | 4.7/5 |
| Manrose XF100S | Budget | 12 | 30 | 4.3/5 |
| Greenwood Airvac CV2GLS | High Airflow | 22 | 28 | 4.5/5 |
| Xpelair Simply Silent DX100 | Silent Operation | 11 | 21 | 4.4/5 |
| EnviroVent Vortice 100 | Continuous Run | 14 | 26 | 4.6/5 |
Vent-Axia Lo-Carbon Selwyn 100mm
Best OverallPros
- Very quiet at 24 dB
- Low running cost (3.2 W)
- Responsive humidistat
Cons
- Higher upfront price
- Plastic grille feels basic
The Vent-Axia Lo-Carbon Selwyn is a 100mm axial fan that combines energy efficiency with quiet performance. Its Lo-Carbon motor uses just 3.2 W, making it one of the most economical fans to run. The built-in humidistat is adjustable and reacts quickly to steam, turning the fan on when needed and off after a set delay.
Owner reviews consistently praise its low noise level, which is barely audible in a small bathroom. The fan is suitable for rooms up to about 4 square meters. Installation is straightforward for a standard 100mm wall or window opening. The three-year warranty adds peace of mind for a product that runs daily.
Manrose XF100S
Best BudgetPros
- Very affordable
- Simple to install
- Includes a backdraught shutter
Cons
- Noisy compared to premium fans
- No built-in humidistat
The Manrose XF100S is a basic 100mm axial fan that does the job without extras. It moves 12 L/s of air, which is adequate for small bathrooms under 3 square meters. The unit includes a backdraught shutter to prevent cold air from entering when the fan is off.
Owner feedback notes that it is noticeably louder than more expensive models, but for the price, the performance is acceptable. It is controlled by a separate light switch or pull cord, so you must remember to turn it on and off. It is a solid choice for a rental property or a tight budget.
Greenwood Airvac CV2GLS
Best High AirflowPros
- High airflow for larger rooms
- Centrifugal design for ducted installations
- Low power consumption
Cons
- Bulkier than axial fans
- Higher price point
The Greenwood Airvac CV2GLS is a centrifugal fan that delivers 22 L/s of airflow, making it ideal for bathrooms up to 6 square meters or those with long duct runs. Centrifugal fans generate more pressure than axial models, so they work better when the air has to travel through ducting.
It features a built-in humidistat and a timer, allowing it to run automatically after a shower. Owner reviews highlight its effective moisture removal and relatively quiet operation for a high-power fan. The unit is larger and requires more space for installation, but it is a top performer for demanding applications.
Xpelair Simply Silent DX100
Best Silent OperationPros
- Extremely quiet at 21 dB
- Low power consumption
- Sleek, modern design
Cons
- Lower airflow than rivals
- No built-in humidistat
The Xpelair Simply Silent DX100 is engineered for whisper-quiet operation. At just 21 dB, it is one of the quietest fans on the market, making it perfect for bathrooms near bedrooms. It is a 100mm axial fan that moves 11 L/s of air, which is sufficient for small rooms.
Owner reviews often mention how unobtrusive it is, even when running at full speed. The fan is controlled by a separate switch and does not include a humidistat or timer. It is best for those who prioritize silence over automation and higher airflow.
EnviroVent Vortice 100
Best Continuous RunPros
- Designed for continuous low-speed running
- Boosts to high speed on demand
- Very energy efficient
Cons
- More expensive than standard fans
- Installation requires specific wiring
The EnviroVent Vortice 100 is a continuous running fan that operates at a low background speed to maintain air quality. When humidity rises, it automatically boosts to a higher speed for rapid extraction. This makes it ideal for bathrooms with no windows or those prone to condensation.
Owner reviews appreciate the constant airflow and the automatic boost function. At 26 dB on low speed, it is barely noticeable. The fan requires a permanent live supply, so installation is slightly more complex than a standard fan. It is a premium choice for managing persistent moisture.
What to Check Before Buying a Bathroom Extractor Fan
What size fan do I need?
The fan size is determined by the diameter of the duct opening, typically 100mm or 150mm. A 100mm fan is suitable for most standard bathrooms up to 4-5 square meters. For larger rooms or longer duct runs, a 150mm fan or a centrifugal model will provide better airflow.
What is airflow rate?
Airflow is measured in liters per second (L/s). Building regulations in the UK recommend a minimum of 15 L/s for a bathroom with a toilet, or 6 L/s for a bathroom without. Higher rates (20-25 L/s) are better for larger rooms or those with showers.
What is the difference between axial and centrifugal fans?
Axial fans are simpler and cheaper, moving air in a straight line. They are best for short, straight duct runs. Centrifugal fans (also called mixed-flow) use a spinning impeller to generate higher pressure, making them better for longer or curved ducting.
What features should I look for?
Key features include a built-in humidistat (turns on automatically when humidity rises), a timer (keeps the fan running after you leave), and a backdraught shutter (prevents cold air from entering). Some fans also have an integrated light or a pull cord for manual control.
How noisy should a bathroom fan be?
Noise is measured in decibels (dB). A fan at 20-25 dB is very quiet, suitable for bedrooms. Fans at 30-35 dB are moderate, while anything above 40 dB can be intrusive. Check the noise rating before buying, especially for bathrooms near sleeping areas.
Mistakes to Avoid
Buying a fan that is too small. A fan with insufficient airflow will not clear steam effectively, leading to mold. Always measure your bathroom and calculate the required L/s rate.
Ignoring duct length and bends. Long or kinked ducting reduces performance. Use smooth, rigid ducting where possible and keep bends to a minimum.
Forgetting about noise. A loud fan can be annoying, especially in a small house. Check the dB rating and read owner reviews for real-world noise levels.
Skipping a humidistat or timer. Manual fans rely on you remembering to turn them on and off. An automatic sensor or timer ensures the fan runs long enough to dry the room.
Not checking the warranty. Fans run for hours each day, so a longer warranty (3-5 years) indicates better build quality and reliability.
FAQs
Do I need a bathroom extractor fan if I have a window?
While a window can be opened, an extractor fan is more effective at removing moisture quickly and works even when you are not home. Building regulations often require a fan in new bathrooms.
How do I clean a bathroom extractor fan?
Turn off the power, remove the grille, and vacuum the blades and housing. Wipe the grille with a damp cloth. Clean every 3-6 months to maintain airflow.
Can I install a bathroom extractor fan myself?
If you are comfortable with basic electrical work and cutting a hole in the wall, you can install a fan. However, any work involving mains wiring should be done by a qualified electrician to comply with regulations.
What is the best location for a bathroom extractor fan?
The fan should be installed as close to the shower or bath as possible, but not directly above it. It should be on an external wall or connected to ducting that leads outside.
How long should a bathroom extractor fan run after a shower?
A timer should be set to run the fan for 15-30 minutes after you leave the room. This ensures all moisture is removed and prevents condensation.
Are bathroom extractor fans required by law?
In the UK, Building Regulations Part F requires adequate ventilation in bathrooms. An extractor fan is the most common way to meet this requirement in rooms without a window.
What is the difference between a humidistat and a timer?
A humidistat turns the fan on when humidity exceeds a set level. A timer keeps the fan running for a set period after it is switched off. Many fans combine both.
Can a bathroom fan be too powerful?
A very powerful fan can create negative pressure, pulling air from other rooms or causing drafts. Choose a fan sized for your room volume.
How do I know if my fan is working properly?
Hold a piece of toilet paper near the grille. If it is held in place, the fan is drawing air. Also check for unusual noise or vibration.
What is a continuous running fan?
These fans run at a low speed all the time to maintain background ventilation, and boost to a higher speed when humidity rises. They are very energy efficient.
Our verdict
The Vent-Axia Lo-Carbon Selwyn is the best overall bathroom extractor fan for its quiet, efficient performance and reliable humidistat. For a budget option, the Manrose XF100S offers solid basic functionality at a low price. Choose the Greenwood Airvac CV2GLS for larger rooms or long duct runs.