We all know that the bathroom is a wet environment, so you need to take extra care to ensure there’s no build-up of mould or other nasty things. Our range of extractor fans will do all the work for you, making sure that all that excess moisture is sucked from the room for good. There’s a huge range available, depending on your needs and tastes, from motion detector fans to extra condensation control.
If you’re looking to purchase a new extractor fan or just generally improve your knowledge then the following guide is the ideal quick read to give you some guidance.
What will be covered starting with the basics and moving into the slightly more advanced:
Water and electricity don’t mix as the combination is very dangerous. To make certain electrical products safe to use in the bathroom the UK Electrical Wiring Regulations split the bathroom into zones and their proximity to water sources.
Zone 0 is in the bath tub.
Zone 1 is the area vertically 2.25m above the bath or in the shower.
Zone 2 extends in all directions for 60cm (0.6m) from Zone 1.
Zone 3 extends laterally for a further 2400mm (2.4m) from zone 2.
These are items which are fitted inside the bath or shower such as lighting for whirlpool baths. Anything installed here must be SELV (a maximum of 12 volts) and a minimum of IPX7. IPX7 means the item is protected against being immersed in water.
Zone 1 and Zone 2
Only two variations of extractor fan can be installed here. These are:
All Safety Extra Low Voltage (SELV) extractors. These are also known as 12v fans or low voltage (LV) fans, they require a transformer which is fitted in zone 3 or outside the zones entirely. These reduce the mains voltage from 240v to 12v. The transformer is usually supplied with the fan.
Regardless of the voltage, any fan has an IP45 rated motor. IP stands for Ingress Protection and an IP45 rating means the motor and all electrical parts are resistant to jets of water from all angles.
Zone 1 and 2 rated fans be default can be installed in Zone 3.
Any and all electrical work must be carried out by a professional, fully qualified electrician.
Zone 3 and Outside the Zones
Regardless of IP rating or voltage, any type extractor fan may be fitted here as these zones are deemed a safe distance from sources of water.
Another type of fan which is installed in the loft above the bathroom is the Inline kind. They are usually connected to the bathroom by a length of ducting. This ducting is the main reason installation can be done in any bathroom zone as it is only the grille and not the fan itself in the bathroom.
As with zones 1 and 2, all electrical work must be carried out by a fully qualified, professional electrician.
It is possible for fans to be wired into your lighting circuit so they are activated when the light is turned on or alternatively on a separate switch allowing for independent operation. Generally extractors have a number of different switching options:
Basic – These are operated using the light or a remote switch only.
Timer – A timer will keep the fan running for a set amount of time after the light has been turned off. This means you don’t have to leave the light on if there is a large build-up of steam.
Humidistat – This type of fan detects the humidity levels in the room. When a pre-set level is reached the fan switches on. These are ideal where lights and the fan are not always turned on manually.
Pull cord – A pull cord allows for local operation and is usually sited near the bathroom light switch or pull.
PIR (passive infrared) – These sensors operate when someone enters the room.
Bathroom extractor fans for the domestic market are normally available in two different sizes. These are 4 inch (100mm) or 6 inch (150mm).
For most bathrooms a 4 inch extractor is perfectly suitable. A 6 inch extractor would only be required for a bathroom which is 9 square metres or more, a bathroom where there isn't any natural ventilation or if the bathroom is north facing or particularly cold.
Extraction rates are the most important things to consider when looking to install a fan. Normally measured in Metres Cubed per Hour (m3/hr) or Litres per Second (L/s). The Building Regulations state that an extractor fan must extract at least 15L/s in a normal domestic bathroom. Most 4 inch fans are capable of this and easily meet the requirement. These days the standard is about 23.5L/s and anything above 25L/s is considered powerful.
Noise levels for axial bathroom extractors range between 35dB(A) and 45dB(A). More powerful centrifugal type fans are a bit louder with levels between 40dB(A) and 55dB(A). As technology progresses fans are getting quieter with some closer to the 20dB(A) level.
One thing not always considered when buying a fan are its aesthetics and style. This is going to be on display in your bathroom and you will more than likely see it every day. No matter how discreet it is you’ll want something that’s attractive as the money you’ve saved on a cheap ugly fan will soon be forgotten.
Consumers are spending more money on their bathrooms and something discreet that blends in with the rest of the room or tiles is fast becoming the popular choice, below are a few examples:
Centrifugal extractors look very similar to Axial fans but there are some subtle differences. They use a different design of impeller which generates much higher exhaust air pressures. This basically means that the extracted air is pushed harder from the room down the ducting and outside.
They are particularly useful where you have long runs of ducting before the old, stale air reaches the outside world, for example ensuite bathrooms or basements.
Axial and Centrifugal fans use fairly consistent impeller sizes (4 and 6 inch) for domestic type installations. Centrifugal extractors are usually larger and also tend to sit proud of the wall so the deeper impeller can be accommodated.
Intermittent extraction is the movement of polluted or moisture rich air at times - for example when someone is taking a shower or cooking. Whether it be operated automatically or manually the ventilation system is only running when it needs to be. This is the most common type of air movement appliance.
The need for continuous ventilation is becoming increasingly popular as newer and renovated properties don’t allow for a natural air movement. With better building techniques, double glazing and a drive for more efficient energy usage, these types of properties suffer from a lack of fresh flowing air.
Mechanical Extract Ventilation - MEV
MEV extraction units simply expel stale air. They operate at low flow rates often between 13L/s and 18L/s. MEV extractors keep air flowing continuously through a building or room, acting rather like a small open window. This type of extraction is known as a Trickle. Some units can have a second Boost setting which can increase flow rates to over 22L/s.
Mechanical Ventilation Heat Recovery
The ventilation industry is investing heavily in mechanical ventilation heat recovery. These units use a heat exchanger to suck fresh warm air back into the property to replace any that was expelled.
These units were developers to solve the issue that ventilation of a continuous nature causes, energy wastage and lost heat.
MVHR is more common as whole house ventilation systems, usually these are centrally positioned, large units with multiple duct points to extract and replace air from multiple rooms.