Envirovent SIL100T Silent-100 Axial Extractor Fan 100mm with Timer

In-Depth Look

Bathroom extractor fans are a Building Regulations requirement in rooms without adequate natural ventilation, but the standard axial fans fitted in many UK homes are noticeably noisy. The Envirovent SIL100T addresses this with an engineering focus on noise reduction without sacrificing extraction performance.

Noise Reduction

At 26.5 dB(A), the SIL100T operates below the level of a quiet whisper. This is achieved through the motor design and blade profile, which moves air efficiently without the turbulence that creates noise in cheaper fans. For en-suites attached to bedrooms, this level of quiet operation makes the difference between a fan that gets switched off to avoid disturbance and one that runs as intended.

Timer Functionality

The adjustable overrun timer is the feature that keeps the fan clearing moisture after you leave, which matters most in bathrooms without openable windows. Whether a particular installation meets Building Regulations Part F is for the installer or building control to confirm. When wired to the bathroom light circuit, the fan starts when the light is turned on and continues running for the set overrun period after the light is switched off. This period is adjustable between 1 and 30 minutes, allowing the installer to set an appropriate duration based on the bathroom size and ventilation requirements.

Electrical Requirements

The timer model requires both a permanent live feed and a switched live from the lighting circuit. This means two cables need to be available at the fan location. In retrofit situations where only a single switched feed exists, the wiring will need to be extended. A qualified electrician should carry out the installation.

Verdict

The Envirovent SIL100T is the bathroom extractor fan to specify when noise is a concern. The 26.5 dB operating level is genuinely quiet, the extraction rate suits typical bathrooms (your installer should confirm it meets the ventilation requirement for your property), and the adjustable timer provides proper moisture control for condensation-prone bathrooms.

How It Compares

The Envirovent SIL100T Silent-100 is a 100mm axial extractor fan with an adjustable overrun timer, designed for bathrooms and toilets. Axial means the blades sit in line with the airflow, like a small propeller in a tube. It runs at 26.5 dB(A), extracts 26 litres per second, uses 10 watts and has an IP45 rating.

The fans most often compared with it are Xpelair Simply Silent and Vent-Axia’s Lo-Carbon and Silhouette ranges, with Manrose and Airflow also common in UK homes. Noise levels, extraction rates and the way the timer is wired vary between models, and manufacturers measure noise in slightly different ways, so compare like for like on the data sheets rather than just the headline figures.

The SIL100T’s selling points in the file are quiet running, the adjustable 1 to 30 minute overrun timer, low power use and the IP45 rating. The timer lets the fan keep clearing moisture after the light is switched off, which matters most in bathrooms without openable windows. Ask your installer to confirm that the fan and timer setting meet the current ventilation requirements for your bathroom.

The file lists three drawbacks. The 26 l/s extraction rate may be insufficient for very large bathrooms. The timer model needs both a permanent live feed and a switched live, so two cables must be available at the fan. And the white cover may yellow over time in steamy environments.

A quiet fan matters most in an en-suite beside a bedroom, because a noisy one tends to get switched off, which defeats its purpose. For a large bathroom or a heavily used shower room, check whether a more powerful fan would suit the space better. Electrical work should be done by a qualified electrician, following the Wiring Regulations and the installation instructions.

Common Questions

How long should the timer run after I leave the room? The SIL100T timer is adjustable from 1 to 30 minutes, and the installer sets it when fitting. A longer run clears more moisture, while a shorter one saves a little energy. The right setting depends on the bathroom size, how steamy it gets and the ventilation requirements. Ask your installer to set it accordingly.

Can I fit it in a shower zone or ceiling? The IP45 rating is described as allowing installation in bathroom zones, but where a fan can go is decided by the zone rules in the Wiring Regulations and the instructions. A qualified electrician should check the position. Ceiling or wall mounting also depends on the ducting route, so check the instructions.

What duct length and bends are acceptable? The fan has a 100mm duct connection. In general, longer ducts and more bends reduce airflow and can increase noise, so keep the run short and direct. The file does not give a maximum length, so follow Envirovent’s installation instructions for the limits.

Do I need a backdraught shutter, and should I fit it to a window or a wall? A shutter helps stop cold air and draughts coming back in when the fan is off, but the file does not say whether one is included. Check what is supplied and what Envirovent recommends. Whether to fit in a wall, window or ceiling depends on the room layout and the duct route, so ask your installer.